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Old Windsor Lock water level

River gauge, River Thames, Berkshire, United Kingdom

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Right now

Very high for mid-October

Water level

0.27m Up 0.09 m over the last 24 hours

0 1 2 Highest onrecord 1.94 m Lowest on record -0.40 m

History

History
0.10.20.3mOct 11Oct 13Oct 14Oct 16Oct 18Top of normal rangeBottom of normal range0.10.20.3mOct 11Oct 14Oct 18Top of normal rangeBottom of normal range
0.10.20.3mSep 18Sep 26Oct 3Oct 10Oct 18Top of normal rangeBottom of normal range0.10.20.3mSep 18Oct 3Oct 18Top of normal rangeBottom of normal range
0.51.0mOct 2025Jan 2026Apr 2026Jul 2026Oct 2026Top of normal rangeBottom of normal range0.51.0mOct 2025Apr 2026Oct 2026Top of normal rangeBottom of normal range
0.51.0mJanMarMayJulSepNov20260.51.0mJanAprJulOct2026

20252026

Water level Normal range (10–90 %) Top of normal rangeBottom of normal range

What this means

The gauge at Old Windsor Lock shows 0.27 m, well above normal for mid-October.

That puts it 0.09 m above the median of 0.18 m for mid-October, based on 21 years of readings. A year ago it stood at 0.14 m (+0.13 m). The record high is 1.94 m, set on February 11, 2014.

The water is rising: up 0.09 m over the past 24 hours. If the rise continues, low-lying paths and riverside parking can go under water. Over the past 30 days it has moved between 0.16 m and 0.30 m.

Autumn rain usually starts to lift rivers again after the summer low.

Compared with 21 years of daily readings for this time of year. How to read levels

Key numbers

Median for this date
0.18 m0.09 m above the median for this date
Normal for this date
0.12 m – 0.23 m8 years in 10 fall in this range (21 years of records)
Normal range
0.10 m – 0.35 m
Same day last year
0.14 m+0.13 m
Lowest and highest in 30 days
0.16 m – 0.30 m
Lowest and highest in 12 months
0.12 m – 0.93 m
Highest on record
1.94 mFebruary 11, 2014
Lowest on record
−0.40 mJune 4, 2003

High water at Old Windsor Lock

Official flood alerts and warnings come from the Environment Agency. They cover areas, not single gauges, so a warning can be in force before this reading looks dramatic.

Keep children and dogs well back from the edge, and stay off flooded footpaths and towpaths.

About the River Thames

River Thames

The River Thames, or simply the Thames, known alternatively in parts as the River Isis, is a river that flows through southern England including London. At 215 miles (346 km), it is the longest river entirely in England and the second-longest in the United Kingdom, after the River Severn.

Read more on Wikipedia

Text and image from Wikipedia and Wikimedia Commons, licensed under CC BY-SA.

Weather at the gauge

Rain in the last 3 days: 2.7 mm. Rain that falls upstream can take hours or days to show up at a river gauge.

18 Sun 13° 7° 0.2 mm, 91% Wind 23 km/h
19 Mon 14° 9° 3.2 mm, 91% Wind 16 km/h
20 Tue 14° 11° 14 mm, 65% Wind 11 km/h
21 Wed 13° 7° 9.5 mm, 47% Wind 25 km/h
22 Thu 12° 6° 0.9 mm, 76% Wind 14 km/h
23 Fri 13° 8° 21 mm, 77% Wind 36 km/h
24 Sat 14° 6° 0.6 mm, 54% Wind 23 km/h

Forecast: Open-Meteo

Sunrise 07:31 AM Sunset 06:05 PM Daylight 10 hr, 33 min First quarter 49%

Map

Other gauges on the River Thames

Gauge Level Compared with normal 24 hours Distance
Windsor ParkRiver gauge, River Thames 3.31 m Normal ±0 2.9 km
Bell WeirRiver gauge, River Thames 0.24 m Very high +0.01 m 3.6 km
Romney LockRiver gauge, River Thames 0.23 m Very high ±0 4.0 km
StainesRiver gauge, River Thames 2.66 m Low −0.01 m 5.3 km
Boveney LockRiver gauge, River Thames 0.20 m Normal +0.01 m 5.9 km
Penton HookRiver gauge, River Thames 0.15 m Normal −0.02 m 7.2 km
Bray LockRiver gauge, River Thames 0.18 m Low +0.01 m 9.8 km
Chertsey LockRiver gauge, River Thames 0.20 m Normal −0.01 m 9.9 km
MaidenheadRiver gauge, River Thames 2.22 m Very low +0.02 m 11 km
Shepperton LockRiver gauge, River Thames 0.14 m Normal −0.01 m 12 km
Boulters LockRiver gauge, River Thames 0.07 m Very low −0.07 m 12 km
Sunbury LockRiver gauge, River Thames 0.27 m Very high +0.03 m 13 km

Nearby gauges

Gauge Level Compared with normal 24 hours Distance
Horton MillRiver gauge, Colne Brook 0.12 m Low −0.01 m 2.8 km
Hythe EndRiver gauge, Colne Brook 0.45 m Normal −0.01 m 3.5 km
PoyleRiver gauge, Poyle Channel 1.49 m Normal ±0 4.1 km
Stanwell MillRiver gauge, River Colne 0.68 m Very high ±0 4.7 km
Staines AshRiver gauge, River Ash 0.10 m Very high ±0 4.7 km
Pound Mill, StainesRiver gauge, Wraysbury River 0.10 m Low ±0 4.8 km
Staines Trading EstateRiver gauge, River Colne 1.19 m Normal −0.01 m 4.9 km

Questions and answers

How does the River Thames at Old Windsor Lock compare with last year?

It is 0.13 m higher than on the same day last year, when the reading was 0.14 m.

What is a normal level for the River Thames at Old Windsor Lock in mid-October?

The median for mid-October is 0.18 m. In 8 years out of 10 the reading falls between 0.12 m and 0.23 m, based on 21 years of records.

Is the river level the same as the depth of the water?

No. The reading is measured from a fixed zero mark at the gauge, so 0.27 m on the gauge does not mean the water is that deep.

What is the water level of Old Windsor Lock today?

On 18 Oct 2026, 12:00 BST, the water level was 0.27 m. Up 0.09 m over the last 24 hours.

Is Old Windsor Lock rising or falling?

Up 0.09 m over the last 24 hours. Up 0.01 m over the last 7 days.

Is the level of Old Windsor Lock normal?

Very high for mid-October. Compared with 21 years of daily readings for this time of year.

What is the highest water level ever recorded at Old Windsor Lock?

The highest level on record is 1.94 m on February 11, 2014. The lowest is −0.40 m on June 4, 2003.

For specialists

Station codes, datum, parameters, data quality and downloads
Operator
Environment Agency
Station code
ea:2703TH (Agency page)
Coordinates
51.46320, -0.56908 (WGS84)
Vertical datum
station datum
Update interval
every 15 minutes
Licence
Open Government Licence v3.0. Contains Environment Agency data licensed under the Open Government Licence v3.0

Published series

ParameterLast valueTime (UTC)Quality
Water level 0.27 m 2026-10-18 11:00 Provisional

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How to cite

Environment Agency: Old Windsor Lock (ea:2703TH). Accessed October 18, 2026 via Nivelmap, https://nivelmap.com/en/united-kingdom/berkshire/old-windsor-lock

How we check values

Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.