North Thames River at St. Marys
Water level and flow at gauge 02GD005, Ontario. The flow is below normal for October (34% of the median). In the last 24 hours it has been steady.
Latest reading Oct 25, 7 AM local standard time (2 hours ago) · data checked · we check every 30 minutes
Compared with a normal October
Normal for October (middle half of 75 years of monthly averages): 2.08 m³/s73.6 cfs – 9.93 m³/s351 cfs, median 4.25 m³/s150 cfs. Right now it is at 34% of the median.
March 19, 1948 · approved records 1948–2025 (HYDAT). Right now the flow is 0% of that record.
88% lower than on October 25, 2025 (11.9 m³/s420 cfs)
approved daily mean (HYDAT)
Last 30 days
Hourly readings · shaded: normal range for this month
This year compared with past years
Daily flow
Normal range: monthly averages of 74 years (lighter band: 10th–90th percentile). Past years: approved daily means from HYDAT, the Water Survey of Canada archive (the latest year published is 2025). 2026: daily means of the provisional real-time readings collected by Canada River Levels since October 22, 2026.
Weather near this gauge
Sunny. Becoming a mix of sun and cloud this afternoon. High 18. UV index 4 or moderate.
A few clouds. Low 7.
Cloudy. High 14. UV index 3 or moderate.
Cloudy. Low zero.
Forecast for Stratford (18 km away) from Environment and Climate Change Canada, issued . Full official forecast ↗ · we check for new forecasts every 2 hours.
Nearby gauges
| Trout CreekSt. Marys · 4 km | 5.73 m18.81 ft | Below normal |
| Fish CreekProspect Hill · 8 km | 3.23 m10.61 ft | Normal |
| Avon RiverBelow Stratford · 10 km | 6.31 m20.71 ft | Below normal |
| Trout CreekFairview · 15 km | 11.36 m37.27 ft | Normal |
| Avon RiverAbove Stratford · 22 km | 6.22 m20.39 ft | Normal |
| North Thames RiverMitchell · 22 km | 3.61 m11.83 ft | Normal |
About this gauge
Station: 02GD005 · North Thames River at St. Marys
Location: 43.2558, -81.1456 · Ontario
Same river: Below Fanshawe Dam, Mitchell
Water levels are measured from a local reference point at each gauge, not from sea level, so they cannot be compared between gauges.
Official sources
For flood warnings, advisories and approved data, always use these official services:
Questions
What is the water level of the North Thames River at St. Marys today?
The latest reading (Oct 25, 7 AM, local standard time) is 2.92 m (9.58 ft) with a flow of 1.43 m³/s (50.5 cfs).
Is the North Thames River at St. Marys high right now?
The flow is below normal for October (34% of the median).
Is the North Thames River rising or falling?
In the last 24 hours it has been steady.
What is the highest flow ever recorded on the North Thames River at St. Marys?
770 m³/s (27,192 cfs) on March 19, 1948, the highest instantaneous flow in the approved records of the Water Survey of Canada (1948–2025). Events after 2025 are not yet in the approved archive.
How does the North Thames River at St. Marys compare with a year ago?
The flow is 88% lower than on October 25, 2025 (11.9 m³/s (420 cfs), approved daily mean (HYDAT)).
Where does this data come from?
Gauge 02GD005 of the Water Survey of Canada (Environment and Climate Change Canada). Real-time data are provisional and may be revised. We check for new readings every 30 minutes. Canada River Levels is not an official source.