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North Thames River at St. Marys water level

River gauge, North Thames River, Ontario, Canada

Directions

Low for mid-October

Water level

2.93m Steady over the last 24 hours

Flow
1.52 m³/s
3.0 3.2

History

3.03.2mOct 12Oct 13Oct 15Oct 17Oct 183.03.2mOct 12Oct 15Oct 18
3.03.2mSep 19Sep 26Oct 3Oct 11Oct 183.03.2mSep 19Oct 3Oct 18
3.03.54.0mOct 2025Jan 2026Apr 2026Jul 2026Oct 20263.03.54.0mOct 2025Apr 2026Oct 2026
3.03.54.0mJanMarMayJulSepNov20263.03.54.0mJanAprJulOct2026

20252026

Water level Normal range (10–90 %)

What this means

At 2.93 m, the North Thames River at St. Marys is below normal for mid-October.

That puts it 0.05 m below the median of 2.98 m for mid-October, based on 21 years of readings. A year ago it stood at 2.89 m (+0.04 m).

The level has held steady over the past 24 hours. Without real rain upstream, that is unlikely to change quickly. Over the past 30 days it has moved between 2.91 m and 3.10 m.

Fall is often low-water season on rivers, and it usually takes a few days of steady rain to change that.

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

Key numbers

Median for this date
2.98 m0.05 m below the median for this date
Normal for this date
2.90 m – 3.32 m8 years in 10 fall in this range (21 years of records)
Same day last year
2.89 m+0.04 m
Lowest and highest in 30 days
2.91 m – 3.10 m
Lowest and highest in 12 months
2.91 m – 4.25 m

Conditions at North Thames River at St. Marys

Low water means shallow riffles on canoe trips and warmer water for fish.

Flood advisories come from the provincial river forecast centre.

About the North Thames River

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

Weather at the gauge

Rain in the last 3 days: 2.0 mm. Rain that falls upstream can take hours or days to show up at a river gauge.

18 Sun 16° 1° – Wind 23 km/h
19 Mon 18° 3° – Wind 16 km/h
20 Tue 17° 4° – Wind 21 km/h
21 Wed 17° 4° – Wind 12 km/h
22 Thu 19° 7° – Wind 16 km/h
23 Fri 15° 5° – Wind 17 km/h
24 Sat 17° 4° – Wind 19 km/h

Forecast: Open-Meteo

Sunrise 07:42 AM Sunset 06:38 PM Daylight 10 hr, 56 min First quarter 54%

Map

Other gauges on the North Thames River

Gauge Level Compared with normal 24 hours Distance
North Thames River near ThorndaleRiver gauge, North Thames River 1.53 m Normal −0.01 m 12 km
North Thames River near MitchellRiver gauge, North Thames River 3.61 m Normal ±0 22 km
North Thames River below Fanshawe DamRiver gauge, North Thames River 6.22 m Low −0.01 m 24 km

Nearby gauges

Gauge Level Compared with normal 24 hours Distance
Trout Creek near St. MarysRiver gauge, Trout Creek 5.75 m Normal ±0 3.9 km
Fish Creek near Prospect HillRiver gauge, Fish Creek 3.27 m Normal −0.01 m 8.4 km
Avon River below StratfordRiver gauge, Avon River 6.31 m Normal −0.01 m 10 km
Trout Creek near FairviewRiver gauge, Trout Creek 11.37 m Normal ±0 15 km
Avon River above StratfordRiver gauge, Avon River 6.22 m Normal −0.01 m 22 km
Middle Thames River at ThamesfordRiver gauge, Middle Thames River 8.84 m Normal −0.02 m 25 km
Little Ausable River near Lucan CrossingRiver gauge, Little Ausable River 2.53 m Normal −0.02 m 26 km

Questions and answers

How does the North Thames River at St. Marys compare with last year?

It is 0.04 m higher than on the same day last year, when the reading was 2.89 m.

What is a normal level for the North Thames River at St. Marys in mid-October?

The median for mid-October is 2.98 m. In 8 years out of 10 the reading falls between 2.90 m and 3.32 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 2.93 m on the gauge does not mean the water is that deep.

What is the water level of North Thames River at St. Marys today?

On Oct 18, 2026, 07:00 PM EDT, the water level was 2.93 m. Steady over the last 24 hours.

Is North Thames River at St. Marys rising or falling?

Steady over the last 24 hours. Steady over the last 7 days.

Is the level of North Thames River at St. Marys normal?

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

How often is this data updated?

Environment and Climate Change Canada – Water Survey of Canada publishes a new reading every hour. This page refreshes within minutes of each update.

For specialists

Station codes, datum, parameters, data quality and downloads
Operator
Environment and Climate Change Canada – Water Survey of Canada
Station code
eccc:02GD005 (Agency page)
Coordinates
43.25575, -81.14562 (WGS84)
Vertical datum
station datum (assumed datum)
Update interval
every hour
Licence
Open Government Licence – Canada. Contains information licensed under the Open Government Licence – Canada

Published series

ParameterLast valueTime (UTC)Quality
Water level 2.93 m 2026-10-18 23:00 Provisional
Flow 1.52 m³/s 2026-10-18 23:00 Provisional

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How to cite

Environment and Climate Change Canada – Water Survey of Canada: North Thames River at St. Marys (eccc:02GD005). Accessed October 18, 2026 via Nivelmap, https://nivelmap.com/en/canada/ontario/north-thames-river-at-st-marys

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.

Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer