A Viking Longship, Budapest → Regensburg, 11 September — The Daily River Watch

The Daily River Watch

Monday 7 September 2026

River levels this morning — not the levels expected on your sailing dates

Rain check: about 20 mm of rain is forecast above Pfelling over fourteen days. Budapest gets almost none. The forecast reaches 20 September. It does not change any status on this page.

1port far below the line
2ports below the line
0ports above the line
1port on lock-controlled reaches
1port with no line to compare
0ports on stretches we watch no gauge on
0ports with no river transit recorded
0ports where the ship is not sailing

What the statuses mean — each one is measured against the level we estimate a ship of this class needs

▼ Far below the line The measured level is under half of Waterlogged's reference line for a ship of this class.
▼ Below the line The measured level is below Waterlogged's reference line for a ship of this class. It is not yet under half that level.
✓ Above the line The measured level is at or above Waterlogged's reference line for a ship of this class.
⚓ Lock-controlled Locks hold the level on this stretch, so low water rarely stops a ship here. High water, maintenance, closures, restrictions on the locks and the cruise line's own decision can still affect a day.
— No line published The reading is real. Nobody publishes a level for this stretch to measure it against.

— No reading yet We include this location on your daily schedule but there is no data available.
— No gauge on this stretch We watch no gauge on this stretch of river. There is no reading for the day and no line to measure one against. We are not telling you the water is fine, and we are not telling you anything holds it at a working level — those are things we have not established here.
⚑ In port The ship is in port on this day. Our record holds no river transit for it, so there is no stretch of river to read. That is what we hold, not a claim about where the ship goes.
⌂ Not sailing The ship does not sail on this day. Your itinerary spends it on land, so there is no river level to read and no low-water question to answer.

A gauge level is not the depth of the navigable channel, not the room under your ship's keel, and not your ship's draft. The rain forecast further down uses one more status of its own, temporarily unavailable, when that feed is missing or out of date.

The official forward outlook

Waterlogged does not provide its own independent future river depth forecast. We show today's gauge reading and compare them with our own reference lines and other historic data. Where Waterlogged has received licenses, it includes river forecasts and clearly identifies the sources where they are from. Waterlogged provides direct links to the gauge forecasts from national providers. BfG has given us permission to show their six week forecasts.

Your daily sailing schedule

Below are the ports you travel to and the depth of the water, as of today's date, and how much water is needed for your ship to sail. A graph shows the median or normal river depth.

Two words will help. A is a riverside station that measures water level. Your ship's is how deep it sits in the water. This affects how much water it needs below the hull.

Day1–2

Budapest

Fri 11 – Sat 12 September · Hungary

Lock-controlled

Locks hold this water at a working level, so low water is far less likely to affect this stretch. Other things still can.

Locks hold the level here, so low water rarely stops a ship.

Full details

The water here is held at a working level by locks. Rainfall does not set it.

What sets the level	locks
Kind of water	a reach held at a working level by locks
Level reading	no level reading is published for this stretch
Sensitive to low water	far less than a free-flowing stretch

Low water does not close this stretch of river; a lock failure or a flood would. High water, maintenance, a closure or a restriction on the locks can still affect a day here, and so can the cruise line's own decision.

Official forecast: — German federal waterway notices

Published by / ELWIS.

No water-level product applies to this day. This water is held at a working level by locks, so there is no gauge reading that would change your day.

What can affect a day like this is a lock outage or maintenance closure. That is announced through ELWIS, the official notices-to-skippers channel — in the authority's own words, before anyone else repeats them.

For this day, check the official notices rather than the levels.

https://www.elwis.de/

Day3–4

Vienna

Sun 13 – Mon 14 September · Austria

Far below the line

The measured level is under half of Waterlogged's reference line for a ship of this class.

Scale 0–250 cm

50 cm below Waterlogged’s reference line

That is how far today's measured level sits below the line we estimate a ship of this class needs. The level it is measured against is our own estimate, not a figure from the cruise line.

Water level now (7 September)	10 cm
Waterlogged’s	60 cm
Normal for 13 September (median for 1991–2025)	201 cm

Falling — the river level fell 24 cm in the last three days.

On the record: For 1991–2025, we checked the eleven days around this date. Budapest’s lowest daily average was 62 cm, in 2003. Today’s reading is 10. That is below every one of the 385 readings in that window.

Water levels are measured at the Budapest gauge – Observation from / General Directorate of Water Management, provided through .
Waterlogged estimated level — our own level for this stretch, set from 35 years of records: every cruise-season day below it fell within a documented disruption. No authority publishes a figure here.

Current level
Past average for this date
WLSN — Waterlogged’s (60 cm)
Measured level below that line
EuRIS official water-level prediction for Budapest, from originator Országos Vízügyi Főigazgatóság (OVF) · Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST · API/Service Hydrometeo v3 incorporated from EuRIS (eurisportal.eu) · Országos Vízügyi Főigazgatóság (OVF) / General Directorate of Water Management

The official prediction for this gauge

EuRIS official water-level prediction for Budapest Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST

EuRIS official water-level prediction for Budapest

API/Service Hydrometeo v3 incorporated from EuRIS (eurisportal.eu). Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST.

Országos Vízügyi Főigazgatóság (OVF) / General Directorate of Water Management — EuRIS names Országos Vízügyi Főigazgatóság (OVF) as the source of this gauge series.

EuRIS publishes no issue time with this prediction, so the time above is when we retrieved it, not when EuRIS made it.

EuRIS's own predicted figures for Budapest, in cm at the gauge.
Time at the gauge	Water level (cm)
Mon 7 Sep, 19:00	9
Tue 8 Sep, 01:00	6
Tue 8 Sep, 07:00	5
Tue 8 Sep, 13:00	5
Tue 8 Sep, 19:00	5
Wed 9 Sep, 01:00	5
Wed 9 Sep, 07:00	5
Wed 9 Sep, 13:00	6
Wed 9 Sep, 19:00	8
Thu 10 Sep, 01:00	9
Thu 10 Sep, 07:00	10
Thu 10 Sep, 13:00	12
Thu 10 Sep, 19:00	14
Fri 11 Sep, 01:00	17
Fri 11 Sep, 07:00	21
Fri 11 Sep, 13:00	27
Fri 11 Sep, 19:00	33
Sat 12 Sep, 01:00	38
Sat 12 Sep, 07:00	41
Sat 12 Sep, 13:00	45
Sat 12 Sep, 19:00	46
Sun 13 Sep, 01:00	46
Sun 13 Sep, 07:00	45

23 figures, from Mon 7 Sep, 19:00 to Sun 13 Sep, 07:00, in local time at the gauge.

Every figure is EuRIS's own, in centimetres at the gauge. Nothing between two figures is filled in by us, and nothing is added beyond the last one.

EuRIS prediction run 7b297e1b-cdc9-4a51-854b-8feddee4e468.

The EuRIS portal, where this prediction is published (opens in a new tab)

Országos Vízügyi Főigazgatóság (OVF)’s own river information service (opens in a new tab)

Predicted water levels are from EuRIS. Waterlogged only reports historical and current data.

Every figure above is a water level at the gauge, in centimetres. It is not the depth of water under a ship and it is not a ship's draft.

Official forecast: water-level forecast for Budapest

Published by Országos Vízjelző Szolgálat (), Hungary’s national forecasting service, under OVF.

The button below opens the official water-level forecast for this stretch — a simple table, about six days ahead. It shows the level in centimetres at the Budapest gauge, the same way this page shows it, so the numbers line up directly.

Don't be surprised by a negative number: the gauge's zero point sits above the riverbed, so readings below zero are real measurements, not errors.

As you read the forecast, compare each day's number with the line — our estimated level for this stretch, set from 35 years of records: every cruise-season day below it fell within a documented disruption. That estimate is ours alone: no cruise line or authority publishes an official figure here.

https://www.hydroinfo.hu/tables/ENG/442027H.html

Day5

Krems

Tuesday 15 September · Austria

No line published

This is a real reading. There is nothing published to measure it against.

Scale 0–300 cm

95 cm
measured

Nobody publishes a target level for this stretch, so there is nothing to measure the reading against. We show the reading and the direction, and nothing more.

Water level now (7 September)	95 cm
Normal for 15 September (median for 2002–2026)	260 cm

Falling — the river level fell 12 cm in the last three days.

Water levels are measured at the Kienstock gauge – Observation from , provided through .
No official data — the reading is official; there is simply nothing published to compare it against.

Current level
Past average for this date
Measured level below that line
EuRIS official water-level prediction for Kienstock, from originator viadonau · Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST · API/Service Hydrometeo v3 incorporated from EuRIS (eurisportal.eu) · Quelle: viadonau

The official prediction for this gauge

EuRIS official water-level prediction for Kienstock Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST

EuRIS official water-level prediction for Kienstock

API/Service Hydrometeo v3 incorporated from EuRIS (eurisportal.eu). Waterlogged retrieved this prediction: 7 Sep 2026, 12:16 CEST.

Quelle: viadonau — EuRIS names viadonau as the source of this gauge series.

EuRIS publishes no issue time with this prediction, so the time above is when we retrieved it, not when EuRIS made it.

EuRIS's own predicted figures for Kienstock, in cm at the gauge.
Time at the gauge	Water level (cm)
Mon 7 Sep, 12:00	119
Mon 7 Sep, 13:00	119
Mon 7 Sep, 14:00	119
Mon 7 Sep, 15:00	119
Mon 7 Sep, 16:00	118
Mon 7 Sep, 17:00	118
Mon 7 Sep, 18:00	118
Mon 7 Sep, 19:00	117
Mon 7 Sep, 20:00	117
Mon 7 Sep, 21:00	117
Mon 7 Sep, 22:00	117
Mon 7 Sep, 23:00	117
Tue 8 Sep, 00:00	116
Tue 8 Sep, 01:00	116
Tue 8 Sep, 02:00	116
Tue 8 Sep, 03:00	115
Tue 8 Sep, 04:00	116
Tue 8 Sep, 05:00	117
Tue 8 Sep, 06:00	118
Tue 8 Sep, 07:00	119
Tue 8 Sep, 08:00	119
Tue 8 Sep, 09:00	120
Tue 8 Sep, 10:00	121
Tue 8 Sep, 11:00	122
Tue 8 Sep, 12:00	122
Tue 8 Sep, 13:00	123
Tue 8 Sep, 14:00	124
Tue 8 Sep, 15:00	124
Tue 8 Sep, 16:00	125
Tue 8 Sep, 17:00	125
Tue 8 Sep, 18:00	125
Tue 8 Sep, 19:00	125
Tue 8 Sep, 20:00	125
Tue 8 Sep, 21:00	125
Tue 8 Sep, 22:00	125
Tue 8 Sep, 23:00	125
Wed 9 Sep, 00:00	124
Wed 9 Sep, 01:00	124
Wed 9 Sep, 02:00	123
Wed 9 Sep, 03:00	123
Wed 9 Sep, 04:00	122
Wed 9 Sep, 05:00	122
Wed 9 Sep, 06:00	121
Wed 9 Sep, 07:00	121
Wed 9 Sep, 08:00	121
Wed 9 Sep, 09:00	121
Wed 9 Sep, 10:00	120
Wed 9 Sep, 11:00	120
Wed 9 Sep, 12:00	120
Wed 9 Sep, 13:00	120
Wed 9 Sep, 14:00	120
Wed 9 Sep, 15:00	120
Wed 9 Sep, 16:00	120
Wed 9 Sep, 17:00	120
Wed 9 Sep, 18:00	120
Wed 9 Sep, 19:00	120
Wed 9 Sep, 20:00	120
Wed 9 Sep, 21:00	120
Wed 9 Sep, 22:00	120
Wed 9 Sep, 23:00	120
Thu 10 Sep, 00:00	120
Thu 10 Sep, 01:00	120
Thu 10 Sep, 02:00	120
Thu 10 Sep, 03:00	120
Thu 10 Sep, 04:00	120
Thu 10 Sep, 05:00	120
Thu 10 Sep, 06:00	120
Thu 10 Sep, 07:00	121
Thu 10 Sep, 08:00	121
Thu 10 Sep, 09:00	122
Thu 10 Sep, 10:00	123
Thu 10 Sep, 11:00	124

72 figures, from Mon 7 Sep, 12:00 to Thu 10 Sep, 11:00, in local time at the gauge.

Every figure is EuRIS's own, in centimetres at the gauge. Nothing between two figures is filled in by us, and nothing is added beyond the last one.

EuRIS prediction run dca61795-2a7d-479a-8236-60f37e5f92dc.

The EuRIS portal, where this prediction is published (opens in a new tab)

viadonau’s own river information service (opens in a new tab)

Predicted water levels are from EuRIS. Waterlogged only reports historical and current data.

Every figure above is a water level at the gauge, in centimetres. It is not the depth of water under a ship and it is not a ship's draft.

Official forecast: station page — Kienstock, the Wachau reference gauge

Published by , the Austrian waterway company, through DoRIS.

No German federal product covers the Austrian Danube. Austria's own navigation service publishes a Kienstock page in English. Its graph also shows a forward series.

On that graph the measured line is labelled . The forward one is labelled . The forward values run several days ahead. Austria notes that Kienstock forecasts are meant for low-water situations.

Then stop looking for a target level, because there is not one. Austria publishes a figure for Kienstock but no figure to pair with it. A level without a depth cannot be turned into a target for your ship, and we will not invent one.

What you can read is the direction of change. You also know that locks keep this stretch full anyway.

https://www.doris.bmimi.gv.at/en/fairway-information/water-levels/kienstock

Day6

Passau

Wednesday 16 September · Germany

Below the line

The measured level is below the published low-water reference for this stretch.

Scale 0–500 cm

76 cm below Waterlogged’s reference line

That is how far today's measured level sits below the line we estimate a ship of this class needs. The level it is measured against is our own estimate, not a figure from the cruise line.

Water level now (7 September)	214 cm
Published for this stretch	290 cm
Normal for 16 September (median for 2015–2026)	308 cm

Falling — the river level fell 9 cm in the last three days.

On the record: For 2015–2025, we checked the eleven days around this date. Pfelling’s lowest daily average was 242 cm, in 2020. Today’s reading is 214. That is below every one of the 121 readings in that window.

Water levels are measured at the Pfelling gauge – German federal waterways gauge service (PEGELONLINE).
Published low-water reference — the waterway authority's own figure for this stretch, not a requirement set by your cruise line.

Current level
Past average for this date
WLSN — Published for this stretch (290 cm)
Measured level below that line
BfG’s own 6-week outlook: one block for each whole published week · the tops of 4 weeks' ranges run past the top of this frame · BfG issued this forecast: 2026-09-03 · Bundesanstalt für Gewässerkunde (BfG)

The official forecast for this gauge

BfG publishes no 14-day forecast for this gauge.

BfG's 6-week outlook for Pfelling BfG issued this forecast: 2026-09-03

BfG's 6-week outlook for Pfelling

Published by Bundesanstalt für Gewässerkunde (BfG). BfG issued this forecast: 2026-09-03.

Each line is one whole week, which is how BfG publishes this product. It gives no figure for any single day, and neither do we.

BfG's own weekly figures for Pfelling, in cm at the gauge.
Week	Lower	Middle	Upper
3–9 September	159	177	198
10–16 September	126	191	301
17–23 September	113	227	488
24–30 September	97	202	452
1–7 October	102	203	433
8–14 October	106	206	428

The three columns are BfG's own 5th, 50th and 95th percentiles from their weather-driven runs, in centimetres at the gauge.

BfG's own file for Pfelling (opens in a new tab)

Forecast water levels are from BfG. Waterlogged only reports historical and current data.

Every figure above is a water level at the gauge, in centimetres. It is not the depth of water under a ship and it is not a ship's draft.

Official forecast: BfG 14-day forecast for Pfelling, via ELWIS

Published by Bundesanstalt für Gewässerkunde (BfG), published through ELWIS.

Your call here is now inside the daily forecast's fourteen-day horizon. So this block has switched itself from the six-week bands to the daily product.

The button below opens Pfelling's own forecast page directly. Read across to 16 September. Remember the number 290 cm.

BfG publishes a range, not a single line — that spread is their own honest uncertainty. Read the whole of it.

https://www.elwis.de/DE/dynamisch/Wasserstaende/Pegelvorhersage:PFELLING

Day7–8

Regensburg

Thu 17 – Fri 18 September · Germany

Below the line

The measured level is below the published low-water reference for this stretch.

Scale 0–500 cm

76 cm below Waterlogged’s reference line

That is how far today's measured level sits below the line we estimate a ship of this class needs. The level it is measured against is our own estimate, not a figure from the cruise line.

Water level now (7 September)	214 cm
Published for this stretch	290 cm
Normal for 17 September (median for 2015–2026)	308 cm

Falling — the river level fell 9 cm in the last three days.

Current level
Past average for this date
WLSN — Published for this stretch (290 cm)
Measured level below that line
BfG’s own 6-week outlook: one block for each whole published week · the tops of 4 weeks' ranges run past the top of this frame · BfG issued this forecast: 2026-09-03 · Bundesanstalt für Gewässerkunde (BfG)

The official forecast for this gauge

BfG publishes no 14-day forecast for this gauge.

BfG's 6-week outlook for Pfelling BfG issued this forecast: 2026-09-03

BfG's 6-week outlook for Pfelling

Published by Bundesanstalt für Gewässerkunde (BfG). BfG issued this forecast: 2026-09-03.

Each line is one whole week, which is how BfG publishes this product. It gives no figure for any single day, and neither do we.

BfG's own weekly figures for Pfelling, in cm at the gauge.
Week	Lower	Middle	Upper
3–9 September	159	177	198
10–16 September	126	191	301
17–23 September	113	227	488
24–30 September	97	202	452
1–7 October	102	203	433
8–14 October	106	206	428

The three columns are BfG's own 5th, 50th and 95th percentiles from their weather-driven runs, in centimetres at the gauge.

BfG's own file for Pfelling (opens in a new tab)

Forecast water levels are from BfG. Waterlogged only reports historical and current data.

Every figure above is a water level at the gauge, in centimetres. It is not the depth of water under a ship and it is not a ship's draft.

Official forecast: BfG 14-day forecast for Pfelling, via ELWIS

Published by Bundesanstalt für Gewässerkunde (BfG), published through ELWIS.

Your call here is now inside the daily forecast's fourteen-day horizon. So this block has switched itself from the six-week bands to the daily product.

The button below opens Pfelling's own forecast page directly. Read across to 17 September. Remember the number 290 cm.

BfG publishes a range, not a single line — that spread is their own honest uncertainty. Read the whole of it.

https://www.elwis.de/DE/dynamisch/Wasserstaende/Pegelvorhersage:PFELLING

Rain on your route — calculated daily

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

Rain can raise the water level of a river but there is no fixed rule on how much it does. We only report how much the quantity of rainfall has changed the water level before under similar conditions. It is context, not a prediction of a river level.

Licensed rain forecast + what the water level has actually done before

The detailed weather forecast for your route

All rain forecasts use the same scale, 0–12 mm of rain a day, so you can compare them directly. Each column is one day, with its date at the top, then the sky for that day and the daily high in °C.

The days of your own sailing are shaded: 11 September to 18 September.

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

Budapest Danube · Hungary

Far below the line

date, sky and daily high °C

Mo 7 Sep 28° Tu 8 33° We 9 33° Th 10 24° Fr 11 23° Sa 12 27° Su 13 26° Mo 14 27° Tu 15 25° We 16 26° Th 17 26° Fr 18 20° Sa 19 23° Su 20 22°

7 September20 September

14 days · mm/day upstream of this gauge

≈ 6 mm expected upstream over 14 days

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

In our 25 years of Budapest records, the water level has never risen more than a few centimetres after rain this light. Today’s level sits 191 cm below normal for the date. Rain like this does not change that.

This is our reading of the rain forecast, based on what rain has actually done to this river in past years. It is not an official river forecast.

Kienstock Danube · Austria

No line published

date, sky and daily high °C

Mo 7 Sep 25° Tu 8 33° We 9 30° Th 10 19° Fr 11 17° Sa 12 22° Su 13 24° Mo 14 24° Tu 15 22° We 16 24° Th 17 19° Fr 18 21° Sa 19 22° Su 20 21°

7 September20 September

14 days · mm/day upstream of this gauge

≈ 29 mm expected upstream over 14 days

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

At Kienstock the water sits behind , so the dams set this level, not the rain. Rain of this size has changed the water level here in past years without changing anything about getting through.

This is our reading of the rain forecast, based on what rain has actually done to this river in past years. It is not an official river forecast.

Pfelling Danube · Germany

Below the line

date, sky and daily high °C

Mo 7 Sep 23° Tu 8 30° We 9 22° Th 10 20° Fr 11 20° Sa 12 22° Su 13 22° Mo 14 23° Tu 15 23° We 16 20° Th 17 18° Fr 18 19° Sa 19 20° Su 20 20°

7 September20 September

14 days · mm/day upstream of this gauge

≈ 20 mm expected upstream over 14 days

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

Rain drains away faster here than on the Rhine. At Pfelling the extra height from rain is usually half gone in about 16 days. At Kaub it lasts much longer — about 55. In past years this much rain, landing on a river already this low, held the level steady for a week or so. It did not close a gap of 76 cm.

This is our reading of the rain forecast, based on what rain has actually done to this river in past years. It is not an official river forecast.

The rest of your route

Locks and hold the water level at a set height at Budapest. So rain is not a river question at these ports. That is why none of these has a rain forecast. What is left is the weather for your day in town.

ViennaVienna–Budapest Danube · Austria

date, sky and daily high °C

Mo 7 Sep 27° Tu 8 32° We 9 33° Th 10 20° Fr 11 17° Sa 12 22° Su 13 24° Mo 14 26° Tu 15 24° We 16 26° Th 17 18° Fr 18 21° Sa 19 22° Su 20 21°

PassauStraubing–Vilshofen free stretch · Germany

date, sky and daily high °C

Mo 7 Sep 22° Tu 8 30° We 9 23° Th 10 20° Fr 11 20° Sa 12 22° Su 13 22° Mo 14 20° Tu 15 23° We 16 20° Th 17 18° Fr 18 20° Sa 19 19° Su 20 19°

RegensburgStraubing–Vilshofen free stretch · Germany

date, sky and daily high °C

Mo 7 Sep 25° Tu 8 31° We 9 21° Th 10 19° Fr 11 21° Sa 12 22° Su 13 23° Mo 14 23° Tu 15 25° We 16 19° Th 17 18° Fr 18 21° Sa 19 20° Su 20 20°

the same days · 7 September to 20 September · daily highs in °C

Rain forecast by Open-Meteo (commercial licence) · fetched 7 September 2026 at 05:16 UTC · covering 14 days, 7 September to 20 September.

How rain reaches the river — the rules we use the stages, the half-lives and the 2003 warning behind every line above

How rain becomes a water level

A river responds to rain in stages. A nearby shower may matter less than rain far upstream.

Rain fallsWhere the rain lands matters as much as the total.
Ground takes a shareDry ground can hold most of the first rain.
Tributaries bring it downWater arrives from different at different times.
The gauge gets a pulseA can briefly raise the level at the gauge.
Baseflow settles it is the slower supply of stored water. It decides where the level settles.

Why winter rain often does more

Winter ground is usually wetter and cooler. Plants use less water then. Less water also evaporates. More of the same rain can reach the river. In high summer, dry soil and growing plants take more water first. Less water then flows over the land into the river.

What "half-life" means here

The is based on past records. It is the time for half the extra height above the usual seasonal level to fade. It describes persistence, not how many centimetres a storm will add.

Estimated half-life of unusual levels at eligible route gauges
Gauge	Winter-runoff block	Summer-recession block
Pfelling	17.3 daysdrift_params.json → PFELLING.blocks[winter_runoff].half_life_days	15.6 daysdrift_params.json → PFELLING.blocks[summer_recession].half_life_days
Hofkirchen	20.2 daysdrift_params.json → HOFKIRCHEN.blocks[winter_runoff].half_life_days	18.7 daysdrift_params.json → HOFKIRCHEN.blocks[summer_recession].half_life_days
Kaub	32.7 daysdrift_params.json → KAUB.blocks[winter_runoff].half_life_days	55.3 daysdrift_params.json → KAUB.blocks[summer_recession].half_life_days
Cologne	31.1 daysdrift_params.json → KOELN.blocks[winter_runoff].half_life_days	58.0 daysdrift_params.json → KOELN.blocks[summer_recession].half_life_days

Read the difference carefully. A longer summer value at the Rhine gauges does not mean summer rain adds more water. It means an unusual measured level faded more slowly in that set of calendar dates. The block names come from the parameter file; they are not weather seasons or a rain-to-level formula.

Rules of thumb

Use these to read a wet outlook — not to predict a sailing-day level.

After a long dry period, the first roughly 10 mm may mainly soak the soil. Do not expect much change at the gauge before that.

Source: waterlogged/rain_explainer.py → transfer_function.soil_absorption_first_mm.value_mm = 10; explicitly qualitative, not a fitted gauge coefficient.
Look downstream after about 1 day Basel–Maxau, 1–1½ days Maxau–Kaub and ½–1 day Kaub–Cologne; Austrian Danube events spanned 60–118 hours, so there is no honest fixed Danube clock.

Sources: docs/council_alignment/lens_hydrology.md gives Rhine flood-wave and falling-water travel times. docs/climate_evidence_wide_signals.md gives the "Travel time & Alpine share" event range and the no-fixed-lag rule.
A routed rain pulse can briefly raise a gauge. Baseflow is the slower supply of stored water. It decides where the level settles.

Source: waterlogged/rain_explainer.py gives the wording about a rain pulse in each season. The figures in the table above are the fitted half_life_days from drift_params.json.

That is the calculation you have just read. The licence turns this panel from a list of links into a daily reading. It still stops where the evidence stops.

How to read every number on this page

"Water level now" is the authority's measured reading at the gauge named on this page. It uses centimetres from that . It is a level, not a depth of water under your ship. It is not the depth of the either, and it is not your ship's .
"Water level a ship of this class needs" — written WLSN at each end of its bold dashed line on the graphs — is Waterlogged's own arithmetic on published reference figures for that stretch and the draft we assume for that class. It is our line, plainly labelled, and it is not the operator's decision to sail.
The seasonal graph shows two different things. Left of the today line, solid blue shows the levels that were measured. Right of it, the dashed line shows the historical average for each date. It comes from what these gauges recorded on that date in past years. It is not a forecast of this autumn, and we do not draw one. We show it because that average keeps falling through October. That is useful to know before you sail.
Where a line comes from the record — Budapest — the page says so. There is still no maintained-depth model published for the Hungarian Danube, so instead of guessing at one we set our level from what actually happened: in 35 years of readings, every cruise-season day below it fell within a disruption somebody documented at the time.
Where no mark exists — Kienstock — we show the reading and the official marks and stop there.
Where the numbers come from. Measured levels for Kaub, Cologne, Pfelling and Hofkirchen are verified daily averages from . They cover 2015–2026 and are topped up from the live archive. Budapest and Kienstock readings come through and . For those two the solid line on the graph is drawn from our own recording of that live feed, which began in July 2026, so it is short and grows by a day each day; the graph says where it starts. The longer measured archive behind Kienstock is not ours to republish, so we do not draw it and we print no record sentence for it. For Budapest that changed on 17 August 2026: the General Directorate of Water Management gave us written permission to publish its own archive, and the average for each date now stands on 35 years of it. Each "normal for this date" uses a 31-day circular — the middle value, so half of past years were higher and half lower. The averages use 12 years of records on the German gauges, 35 years on Budapest and 25 years on Kienstock, from the projection engine's own doy_median_cm arrays. Record lines use an eleven-day window centred on the port's own date, across each gauge's whole archive. Budapest's levels come from Országos Vízügyi Főigazgatóság (OVF) / General Directorate of Water Management; where we work them into an average, those input data originate from the General Directorate of Water Management.
Nothing here is a forecast. The trend and the graph describe measured moves that have already happened. We do not model your cruise and we do not give you a percentage chance of anything.

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Every morning until the morning after you leave the ship: the reading on the gauge that governs your stretch, what changed overnight, and the river companion — the story of the water you are sailing on. Free.

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Do not see your sailing? We do not report cancelled sailings. Tell us which sailing we are missing and we will add it. You can also email info@rivercruisewatch.com with the cruise line, the ship and the dates.

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A Viking Longship · Romantic Danube

The Daily River Watch

River levels this morning — not the levels expected on your sailing dates

What the statuses mean — each one is measured against the level we estimate a ship of this class needs

The official forward outlook

Your daily sailing schedule

Budapest

Official forecast: ELWISGermany's official waterway service for forecasts, restrictions and notices to skippers. — German federal waterway notices

Vienna

The official prediction for this gauge

EuRIS official water-level prediction for Budapest

Official forecast: OVFHungary's national water authority. Its forecasting service publishes the Budapest table. water-level forecast for Budapest

Krems

The official prediction for this gauge

EuRIS official water-level prediction for Kienstock

Official forecast: DoRISAustria's Danube River Information Services site for water levels and navigation notices. station page — Kienstock, the Wachau reference gauge

Passau

The official forecast for this gauge

BfG's 6-week outlook for Pfelling

Official forecast: BfG 14-day forecast for Pfelling, via ELWIS

Regensburg

The official forecast for this gauge

BfG's 6-week outlook for Pfelling

Official forecast: BfG 14-day forecast for Pfelling, via ELWIS

The detailed weather forecast for your route

Budapest Danube · Hungary

Kienstock Danube · Austria

Pfelling Danube · Germany

The rest of your route

How rain becomes a water level

Why winter rain often does more

What "half-life" means here

Rules of thumb

How to read every number on this page

The Daily River Log Watch — free for this sailing

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Official forecast: — German federal waterway notices

Official forecast: water-level forecast for Budapest

Official forecast: station page — Kienstock, the Wachau reference gauge