Climate averages 1991–2020
St. Catharines weather
by month.
See how the year changes. July has the highest average daily maximum; February has the lowest average monthly precipitation.
Long-term climate patterns, not a forecast for a particular trip.
Across the year St. Catharines averages a daytime high of 12.8°C and a nighttime low of 6.5°C, with about 979 mm of rain on roughly 130 days. July is the warmest month (average high 25.8°C) and January the coolest (-0.3°C). April is the wettest month with 97 mm; February is the driest with 60 mm.
The annual picture
A year in St. Catharines
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 | 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
Nearby cities
- Niagara FallsCanada · 16 kmHigh 12.7°C · Low 6.0°C · 1,014 mm rain a year
- AmherstUnited States · 42 kmHigh 13.1°C · Low 5.6°C · 983 mm rain a year
- Stoney CreekCanada · 43 kmHigh 13.4°C · Low 5.2°C · 918 mm rain a year
- BuffaloUnited States · 43 kmHigh 12.5°C · Low 5.9°C · 1,014 mm rain a year
- OakvilleCanada · 47 kmHigh 12.5°C · Low 5.6°C · 887 mm rain a year
- CheektowagaUnited States · 50 kmHigh 12.9°C · Low 5.4°C · 983 mm rain a year
- HamiltonCanada · 50 kmHigh 12.6°C · Low 6.0°C · 918 mm rain a year
- BurlingtonCanada · 54 kmHigh 12.5°C · Low 5.2°C · 887 mm rain a year
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 limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC-5, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 43.20°, -79.20° (5 km from the city centre). Rain comes from the 0.25° cell at 43.25°, -79.25°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.