Chatham climate — normals and trends
Chatham (Canada) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.2 °C and it receives 897 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 (22.3 °C on average) and the coldest is January (-4.4 °C). Rainfall peaks in June.
Chatham averages 119 frost days, 12 hot days (≥ 30 °C) and 126 rainy days per year.
Chatham has warmed by +1.8 °C between 1940 and 2025, or +0.21 °C per decade. This trend is statistically significant.
The number of frost days there went from about 133 to 105 per year over the period.
The hottest day of the period reached 38.2 °C (on 7 July 1988) and the coldest -27.7 °C (on 20 February 2015).
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
ChathamOntario
- coords
- 42.41°, -82.18°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.2°C
Average daily high
13.2°C
Average daily low
5.1°C
Annual rainfall
897mm
Sunshine / day
8.9h
Mean relative humidity
73%
Average peak wind
21.4km/h
Seasonal range
26.7°C
Frost days (< 0 °C)
119 d/yr
Hot days (≥ 30 °C)
12 d/yr
Rainy days (≥ 1 mm)
126 d/yr
Annual snowfall
80.1 cm
Average feels-like high
11.0 °C
Average feels-like low
1.9 °C
Average peak gust
39.9 km/h
Tropical nights (≥ 20 °C)
22 d/yr
Solar radiation
14.7 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.8 °C
since 1940
+0.2 °C per decade · r² = 0.34 · 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
38.2 °C
7 July 1988
Coldest day
-27.7 °C
20 February 2015
Wettest day
93 mm
20 July 1989
Windiest day
62.9 km/h
15 March 1959
Strongest gust
111.6 km/h
22 March 1955
Hottest feels-like
42.6 °C
14 July 1995
Coldest feels-like
-34.3 °C
24 January 1963
Snowiest day
26.7 cm
25 February 1965
Sunniest day
15.0 h
6 June 1940
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 | -2.4 °C | -1.2 °C | 42 mm | -18 mm |
| Feb | -0.7 °C | -0.4 °C | 57 mm | +1 mm |
| Mar | 9.8 °C | +4.7 °C | 84 mm | +12 mm |
| Apr | 13.7 °C | +1.3 °C | 82 mm | -5 mm |
| May | 17.4 °C | -1.6 °C | 83 mm | -6 mm |
| Jun | 25.8 °C | +1.3 °C | 80 mm | -8 mm |
| Jul | 27.9 °C | +1.2 °C | 109 mm | +25 mm |
| Aug | 25.4 °C | -0.3 °C | 38 mm | -41 mm |
| Sep | 23.9 °C | +2.0 °C | 42 mm | -30 mm |
| Oct | 17.5 °C | +2.2 °C | 55 mm | -14 mm |
| Nov | 8.0 °C | -0.1 °C | 43 mm | -31 mm |
| Dec | 1.2 °C | -0.4 °C | 94 mm | +26 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 Chatham?
Chatham has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.2 °C and it receives 897 mm of precipitation per year.
What is the hottest day ever recorded in Chatham?
The hottest day measured in Chatham between 1940 and 2025 was 7 July 1988, reaching 38.2 °C.
What is the coldest day in Chatham?
The coldest day measured in Chatham between 1940 and 2025 was 20 February 2015, at -27.7 °C.
Does it snow in Chatham?
Yes. Chatham gets on average 80.1 cm of snow per year and has around 119 frost days.
Has the climate of Chatham warmed?
Yes: Chatham warmed by +1.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Chatham?
The wettest day measured in Chatham between 1940 and 2025 was 20 July 1989, with 93 mm of rain in 24 hours.
What was the windiest day in Chatham?
The windiest day measured in Chatham between 1940 and 2025 was 15 March 1959, with winds reaching 62.9 km/h.
What is the warmest month in Chatham?
The warmest month in Chatham is July (22.3 °C on average); the coldest is January (-4.4 °C).
How much does it rain in Chatham?
Chatham receives on average 897 mm of precipitation per year, spread over about 126 rainy days.
Is it sunny in Chatham?
Chatham gets on average 8.9 hours of sunshine per day, roughly 3,249 hours per year over 1940-2025.
What is the biggest single-day snowfall in Chatham?
The heaviest 24-hour snowfall measured in Chatham between 1940 and 2025 was 25 February 1965, with 26.7 cm.
Are there tropical nights in Chatham?
Yes: Chatham has on average 22 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Chatham?
In Chatham, between 1940 and 2025, the highest apparent temperature reached 42.6 °C on 14 July 1995, and the lowest was -34.3 °C on 24 January 1963.
Compare Chatham with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Chatham