Chatham swings 33°C across the year, from 26°C highs in July to -7°C lows in January, and September is usually the wettest month in a year that brings about 961 mm of precipitation. Over 10 years of recorded weather it averages 85 days a year at 25°C or above, 16 of them at 30°C or above, 114 frost nights, and rain on 138 days.
Warmest month
July
26°C average high
Coldest month
January
-7°C average low
Wettest month
September
961 mm a year
Comfortable
4 months
May, June, July and August
Residents
44,000
share this forecast
Most accurate here
European
93/100 CheckWeather Score
Warm days
85 days
a year at 25°C or above
Frost nights
114 nights
a year below 0°C
Rain days
138 days
a year with 1 mm or more
Day counts are from the ERA5 reanalysis for Chatham’s grid square, 2016 to 2025, counted the same way for every city so the numbers compare. A reanalysis square is an area, not a weather station, so it is good for counting days and not for a single day’s record.
The weather map: all three models at once
Env. Canada, European, American side by side around Chatham and nearby towns.Live rain radar →
Loading the three model maps…
Chatham hourly forecast: next 14 hours
consensus of the three models
Rain in the next 24 hours, model by model
each model's own hourly precipitation, side by side
Loading the three models…
Chatham 10-day forecast, out to 14 days
where the models agree, and where they split
Today
Clear
18°5°
models agree
Tomorrow
Cloudy
19°8°
models agree
Mon
Cloudy
19°9°
models agree
Tue
Cloudy
14°6°
±3°
Wed
Cloudy
18°8°
±5°
Thu
Partly cloudy
21°9°
±3°
Fri
Clear
19°7°
±5°
Sat
Cloudy
19°11°
±3°
Sun
Light rain
19°13°
±2°
Mon
Light rain
16°7°
±4°
Tue
Drizzle
10°3°
models agree
Wed
Light drizzle
9°1°
models agree
Thu
Light drizzle
12°5°
±7°
Fri
Cloudy
13°4°
±6°
Chatham, Ontario is at its warmest in Jul (average highs near 26°C) and coldest in Jan (lows around -7°C), with roughly 961 mm of precipitation across the year. Below, compare what Env. Canada, European, American forecast for Chatham right now, and see exactly where they disagree.
average daytime high and overnight low across a typical year (1991-2020)
Jan
-1°
-7°
Feb
3°
-7°
Mar
6°
-3°
Apr
13°
3°
May
19°
7°
Jun
24°
14°
Jul
26°
16°
Aug
25°
16°
Sep
22°
13°
Oct
15°
7°
Nov
8°
1°
Dec
3°
-2°
Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.
How Chatham's weather has changed since 1995
30 years of daily data, 1995-2024, shown as change
+1.0°C
Around Chatham, 2015-2024 averaged 1.0°C warmer than 1995-2004. 5 of the 10 warmest years since 1995 fall in the last ten, and the warmest was 2024.
1995each stripe is one year2024
cooler than averagearound averagewarmer than average
Days above 30°C
3 more days a year
2015-2024 against 1995-2004. Within the normal year-to-year swing
Frost nights
10 fewer nights a year
2015-2024 against 1995-2004, below 0°C. Within the normal year-to-year swing
Average wind
−2%
2015-2024 against 1995-2004. Within the normal year-to-year swing
Bars: each year against the area's 30-year average. Dashed lines: the average of the first and the last ten years.
See the numbers year by year
Year
Temp vs average
Days >30°C vs avg
Frost nights vs avg
Wind vs avg
1995
−1.0°C
+12
+21
+2%
1996
−1.8°C
−8
+27
+2%
1997
−0.9°C
−6
+14
+4%
1998
+1.6°C
+5
−23
−4%
1999
−0.2°C
+1
−4
+2%
2000
−0.6°C
−11
−1
+0%
2001
−0.4°C
−4
−3
−4%
2002
−0.3°C
+7
+17
+2%
2003
−1.5°C
−7
+13
+0%
2004
−0.3°C
−11
−11
+4%
2005
+0.4°C
+20
−1
−4%
2006
+0.7°C
−2
−27
+0%
2007
+0.4°C
+7
+1
+2%
2008
−0.4°C
−10
+8
+6%
2009
−0.5°C
−7
−8
+0%
2010
+0.6°C
+9
−6
+0%
2011
−0.1°C
+3
−5
−2%
2012
+1.2°C
+1
−15
−4%
2013
−0.8°C
−6
+15
+0%
2014
−1.9°C
−11
+20
+0%
2015
−0.7°C
−8
−6
−4%
2016
+0.9°C
+6
−6
+0%
2017
+0.2°C
−10
−18
+2%
2018
−0.4°C
−4
+22
−2%
2019
−0.6°C
−9
+5
+0%
2020
+0.8°C
+11
+2
+0%
2021
+1.4°C
+12
−6
−2%
2022
+0.4°C
+12
+4
+4%
2023
+1.1°C
−5
−17
−5%
2024
+1.9°C
+0
−26
−4%
Source: NASA POWER daily data from the MERRA-2 reanalysis, 1995-2024. Each value describes a grid square of about 50 km around Chatham, not a weather station, and a square that takes in sea or a large lake runs milder than the city itself. That is why this section shows change against the square's own 30-year average rather than counts you could compare with a local station. Rain and snow are left out because their long-term record in this dataset is not consistent over time. "Within the normal year-to-year swing" means the change is smaller than the usual differences between single years.
Which forecast is most accurate in Chatham?
CheckWeather Score, graded against the weather that actually happened
Provider
CheckWeather-score
Temp
Wind
Rain
Run by
European ★ Best
93
/100rank #1
93±0.4°C
98±1.0 km/h
8994% hit
ECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
EC
Env. Canada
87
/100rank #2
85±0.8°C
97±1.4 km/h
8290% hit
Environment and Climate Change CanadaDorval, Québec, Canada
American
86
/100rank #3
89±0.6°C
96±2.2 km/h
7687% hit
NOAA / NCEP (United States)College Park, Maryland, USA
The accuracy above is the measured record. This is your opinion: which forecast service do you trust most in Canada? Give each 1 to 5 stars.
Env. CanadaGEM model
Loading ratings…
EuropeanECMWF
Loading ratings…
AmericanNOAA GFS
Loading ratings…
One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.
Where the models disagree
temperature and rain, judged separately
Day
Temperature
Rain
Today
±2°17° to 19°
models agree0% to 0% chance
Tomorrow
±1°19° to 19°
±2%0% to 2% chance
Mon
±1°18° to 19°
models agree0% to 0% chance
Tue
±3°13° to 16°
models agree0% to 0% chance
Wed
±5°16° to 20°
±2%0% to 2% chance
The models often agree on temperature and still split on rain, and rain is usually what decides whether a plan survives. A wide rain range means the shower is genuinely uncertain, not that the forecast is wrong.
Sunrise and sunset in Chatham
today, local time
Sunrise
07:52
Sunset
18:32
Daylight
10h 40m
Common questions
What's the weather in Chatham today?
Saturday, October 24: Env. Canada, the European and the American model agree on a high near 18° in Chatham today. Tomorrow: cloudy, around 19°, with a 2% chance of rain. The forecast on this page refreshes live.
Will it rain in Chatham today or tomorrow?
Rain looks unlikely in Chatham on Sunday, October 25: no model gives more than 2% (Env. Canada 0%, European 2%, American 0%). On Saturday, October 24 the highest chance of rain from any model is 0%. The hourly strip and the model-by-model rain panel above update live.
Which forecast is most accurate for Chatham?
Over the last 30 days, the European model has been the most accurate for Chatham (CheckWeather Score 93/100), ahead of the Env. Canada at 87. We grade every model against the recorded weather. See the CA accuracy scoreboard for the full method.
What is the warmest month in Chatham?
July is typically the warmest month in Chatham, with average highs around 26°C.
How cold does Chatham get?
The coldest month in Chatham is January, when overnight lows average about -7°C.
How much rain does Chatham get?
Chatham sees roughly 961 mm of precipitation a year, with September usually the wettest month.
Is Chatham getting warmer?
Yes. In NASA's reanalysis for the area around Chatham, 2015-2024 averaged 1.0°C warmer than 1995-2004.
CheckWeather.io on iPhoneFree. No ads, no account.
