Ajax climate — normals and trends
Ajax (Canada) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 7.9 °C and it receives 955 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 August (21.1 °C on average) and the coldest is February (-4.7 °C). Rainfall peaks in November.
Ajax averages 106 frost days, 0 hot days (≥ 30 °C) and 128 rainy days per year.
Ajax 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 121 to 91 per year over the period.
The hottest day of the period reached 30.1 °C (on 9 August 1949) and the coldest -25.1 °C (on 4 January 1981).
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
AjaxOntario
- coords
- 43.85°, -79.03°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
7.9°C
Average daily high
10.2°C
Average daily low
5.8°C
Annual rainfall
955mm
Sunshine / day
8.8h
Mean relative humidity
76%
Average peak wind
27.2km/h
Seasonal range
25.8°C
Frost days (< 0 °C)
106 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
128 d/yr
Annual snowfall
100.9 cm
Average feels-like high
7.3 °C
Average feels-like low
1.6 °C
Average peak gust
39.8 km/h
Tropical nights (≥ 20 °C)
26 d/yr
Solar radiation
14.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.24 · 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
30.1 °C
9 August 1949
Coldest day
-25.1 °C
4 January 1981
Wettest day
77 mm
28 September 1967
Windiest day
69.4 km/h
15 March 1959
Strongest gust
103.7 km/h
3 December 1980
Hottest feels-like
33.9 °C
6 July 2012
Coldest feels-like
-33.9 °C
2 February 1976
Snowiest day
24.2 cm
17 January 2022
Sunniest day
14.9 h
6 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 | -0.1 °C | 41 mm | -37 mm |
| Feb | -0.8 °C | +0.8 °C | 81 mm | +18 mm |
| Mar | 4.8 °C | +3.3 °C | 111 mm | +33 mm |
| Apr | 6.9 °C | +0.8 °C | 70 mm | -20 mm |
| May | 10.7 °C | -0.5 °C | 117 mm | +35 mm |
| Jun | 17.6 °C | 0.0 °C | 45 mm | -27 mm |
| Jul | 23.7 °C | +1.3 °C | 40 mm | -26 mm |
| Aug | 23.2 °C | +0.1 °C | 65 mm | -2 mm |
| Sep | 20.0 °C | +0.1 °C | 35 mm | -50 mm |
| Oct | 15.0 °C | +1.1 °C | 73 mm | -16 mm |
| Nov | 6.8 °C | -0.8 °C | 71 mm | -23 mm |
| Dec | 1.3 °C | -0.9 °C | 102 mm | +11 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 Ajax?
Ajax has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 7.9 °C and it receives 955 mm of precipitation per year.
What is the hottest day ever recorded in Ajax?
The hottest day measured in Ajax between 1940 and 2025 was 9 August 1949, reaching 30.1 °C.
What is the coldest day in Ajax?
The coldest day measured in Ajax between 1940 and 2025 was 4 January 1981, at -25.1 °C.
Does it snow in Ajax?
Yes. Ajax gets on average 100.9 cm of snow per year and has around 106 frost days.
Has the climate of Ajax warmed?
Yes: Ajax warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ajax?
The wettest day measured in Ajax between 1940 and 2025 was 28 September 1967, with 77 mm of rain in 24 hours.
What was the windiest day in Ajax?
The windiest day measured in Ajax between 1940 and 2025 was 15 March 1959, with winds reaching 69.4 km/h.
What is the warmest month in Ajax?
The warmest month in Ajax is August (21.1 °C on average); the coldest is February (-4.7 °C).
How much does it rain in Ajax?
Ajax receives on average 955 mm of precipitation per year, spread over about 128 rainy days.
Is it sunny in Ajax?
Ajax gets on average 8.8 hours of sunshine per day, roughly 3,212 hours per year over 1940-2025.
What is the biggest single-day snowfall in Ajax?
The heaviest 24-hour snowfall measured in Ajax between 1940 and 2025 was 17 January 2022, with 24.2 cm.
Are there tropical nights in Ajax?
Yes: Ajax has on average 26 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ajax?
In Ajax, between 1940 and 2025, the highest apparent temperature reached 33.9 °C on 6 July 2012, and the lowest was -33.9 °C on 2 February 1976.
Compare Ajax with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ajax