St. Catharines climate — normals and trends
St. Catharines (Canada) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.0 °C and it receives 983 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (21.9 °C on average) and the coldest is February (-3.7 °C). Rainfall peaks in April.
St. Catharines averages 101 frost days, 1 hot days (≥ 30 °C) and 135 rainy days per year.
St. Catharines has warmed by +1.5 °C between 1940 and 2025, or +0.18 °C per decade. This trend is statistically significant.
The number of frost days there went from about 115 to 87 per year over the period.
The hottest day of the period reached 32.3 °C (on 9 August 1949) and the coldest -24.8 °C (on 18 February 1979).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
St. CatharinesOntario
- coords
- 43.17°, -79.24°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.0°C
Average daily high
11.8°C
Average daily low
6.3°C
Annual rainfall
983mm
Sunshine / day
8.6h
Mean relative humidity
74%
Average peak wind
22.4km/h
Seasonal range
25.6°C
Frost days (< 0 °C)
101 d/yr
Hot days (≥ 30 °C)
1 d/yr
Rainy days (≥ 1 mm)
135 d/yr
Annual snowfall
98.3 cm
Average feels-like high
9.4 °C
Average feels-like low
3.0 °C
Average peak gust
38.8 km/h
Tropical nights (≥ 20 °C)
29 d/yr
Solar radiation
14.0 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.27 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
32.3 °C
9 August 1949
Coldest day
-24.8 °C
18 February 1979
Wettest day
83 mm
15 October 1954
Windiest day
60.9 km/h
15 March 1959
Strongest gust
106.9 km/h
11 January 2017
Hottest feels-like
37.3 °C
3 September 1953
Coldest feels-like
-32.9 °C
17 January 1982
Snowiest day
30.1 cm
7 February 1942
Sunniest day
14.9 h
5 July 2025
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.2 °C | -0.5 °C | 40 mm | -31 mm |
| Feb | -0.4 °C | +0.2 °C | 84 mm | +20 mm |
| Mar | 6.6 °C | +3.4 °C | 83 mm | +1 mm |
| Apr | 9.6 °C | +0.7 °C | 75 mm | -17 mm |
| May | 14.2 °C | -0.7 °C | 124 mm | +37 mm |
| Jun | 21.4 °C | +0.4 °C | 56 mm | -30 mm |
| Jul | 26.0 °C | +1.4 °C | 56 mm | -31 mm |
| Aug | 24.2 °C | -0.1 °C | 69 mm | -10 mm |
| Sep | 21.3 °C | +0.6 °C | 30 mm | -56 mm |
| Oct | 15.7 °C | +1.1 °C | 80 mm | -6 mm |
| Nov | 7.7 °C | -0.5 °C | 64 mm | -21 mm |
| Dec | 1.8 °C | -0.7 °C | 90 mm | +10 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of St. Catharines?
St. Catharines has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 9.0 °C and it receives 983 mm of precipitation per year.
What is the hottest day ever recorded in St. Catharines?
The hottest day measured in St. Catharines between 1940 and 2025 was 9 August 1949, reaching 32.3 °C.
What is the coldest day in St. Catharines?
The coldest day measured in St. Catharines between 1940 and 2025 was 18 February 1979, at -24.8 °C.
Does it snow in St. Catharines?
Yes. St. Catharines gets on average 98.3 cm of snow per year and has around 101 frost days.
Has the climate of St. Catharines warmed?
Yes: St. Catharines warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in St. Catharines?
The wettest day measured in St. Catharines between 1940 and 2025 was 15 October 1954, with 83 mm of rain in 24 hours.
What was the windiest day in St. Catharines?
The windiest day measured in St. Catharines between 1940 and 2025 was 15 March 1959, with winds reaching 60.9 km/h.
What is the warmest month in St. Catharines?
The warmest month in St. Catharines is July (21.9 °C on average); the coldest is February (-3.7 °C).
How much does it rain in St. Catharines?
St. Catharines receives on average 983 mm of precipitation per year, spread over about 135 rainy days.
Is it sunny in St. Catharines?
St. Catharines gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in St. Catharines?
The heaviest 24-hour snowfall measured in St. Catharines between 1940 and 2025 was 7 February 1942, with 30.1 cm.
Are there tropical nights in St. Catharines?
Yes: St. Catharines has on average 29 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in St. Catharines?
In St. Catharines, between 1940 and 2025, the highest apparent temperature reached 37.3 °C on 3 September 1953, and the lowest was -32.9 °C on 17 January 1982.
Compare St. Catharines with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around St. Catharines