Climate averages 1991–2020
St. Catharines weather
in August.
A warm, moderately wet month: the 2nd warmest and the joint 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a warm month in St. Catharines: daytime highs average 25.1°C and nights cool to about 19.1°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 75 mm of rain on roughly 10 days, which makes August a moderately wet month (the joint 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 57 min on an average August day.
The nearest other city in this atlas is Niagara Falls (16 km away). In August its highs average 24.9°C, about as warm as St. Catharines, with 85 mm of rain.
Among the 86 cities listed in Canada, St. Catharines ranks joint 9th of 86 for the warmest August highs and joint 41st of 86 for the driest August (rainfall, lowest first). The mean August high of those 86 cities is 23.8°C; St. Catharines is 1.3°C warmer than that mean.
From August to September, average highs fall by 3.6°C to 21.5°C, and monthly rainfall rises from 75 mm to 85 mm.
The annual picture
August in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
St. Catharines climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -0.3°C-6.0°C | -6.0°C | 75 | 11.9 | 9.49 h |
| February | 0.0°C-6.6°C | -6.6°C | 60 | 9.1 | 10.510 h |
| March | 4.2°C-2.8°C | -2.8°C | 73 | 10.4 | 11.912 h |
| April | 10.8°C3.0°C | 3.0°C | 97 | 11.7 | 13.413 h |
| May | 17.4°C9.5°C | 9.5°C | 83 | 11.4 | 14.615 h |
| June | 22.8°C15.9°C | 15.9°C | 91 | 11.1 | 15.315 h |
| July | 25.8°C19.4°C | 19.4°C | 88 | 10.8 | 15.015 h |
| August, selected | 25.1°C19.1°C | 19.1°C | 75 | 9.9 | 14.014 h |
| September | 21.5°C15.5°C | 15.5°C | 85 | 9.7 | 12.513 h |
| October | 14.8°C9.4°C | 9.4°C | 92 | 12.0 | 11.111 h |
| November | 8.2°C3.3°C | 3.3°C | 82 | 10.7 | 9.810 h |
| December | 2.9°C-1.7°C | -1.7°C | 77 | 11.6 | 9.19 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Niagara Falls in AugustCanada · 16 kmHigh 24.9°C · Low 18.5°C · 85 mm rain
- Amherst in AugustUnited States · 42 kmHigh 25.0°C · Low 17.7°C · 80 mm rain
- Stoney Creek in AugustCanada · 43 kmHigh 25.8°C · Low 17.6°C · 69 mm rain
- Buffalo in AugustUnited States · 43 kmHigh 24.5°C · Low 18.2°C · 85 mm rain
- Oakville in AugustCanada · 47 kmHigh 25.1°C · Low 18.2°C · 66 mm rain
- Cheektowaga in AugustUnited States · 50 kmHigh 24.8°C · Low 17.5°C · 80 mm rain
- Hamilton in AugustCanada · 50 kmHigh 25.4°C · Low 18.7°C · 69 mm rain
- Burlington in AugustCanada · 54 kmHigh 25.1°C · Low 17.7°C · 66 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for St. Catharines) is explained once on the St. Catharines year overview and on the Sources, method and limits page.