Photo: Rub-a-dub Hedgehog · CC BY 4.0Afternoon heat in Chatham beats that of 89% of Canadian towns
Nights in January average −8.2°C. The wettest month is April; the driest is February. Its January nights stay gentler than in 83% of Canadian towns. Picnics, hikes and garden evenings suit May, June, August and September, with highs of 19–26°C.
Measured at Ridgetown, 26 km east: ECCC’s normals for 1991–2020.
A year in Chatham at a glance
Each month’s typical high and low, in °C.
What stands out about Chatham’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Chatham feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
About 132 frosts and 132 warm days a year
Frost comes from October to May, most of all in January (about 27 nights). About 15 days a year top 30°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
About 903 mm of rain and snow a year
Some 120 days a year see 1 mm of rain or snow or more.
Rain and snow by month
Millimetres
About 91 cm of snow a year
Expect snow from November to April, with about 28 cm in January, the snowiest month. 848th snowiest of 854 towns of 2,500+ in Ontario.
Snowfall by month
Centimetres
Snowfall: New Glasgow, 47 km away (Ridgetown records no complete year of it).
Heating a home in Chatham
92% of a year’s heating need falls between October and April. Months averaging under 10°C: November to April.
The total grows by a degree for every degree a day’s mean sits under 18°C. In heating terms, homes need less heating than 87% of Canadian towns.
Living with Chatham’s climate
What the normals mean for a garden, a day outside and the depth of winter.
Count on about 149 frost-free days: the last frost averages 10 May, the first 6 October.
Highs of 17–27°C with nights of 8°C or more come in May, Jun, Aug and Sep.
Parks & trails →About 15 days a year bring a wind chill under −20, when bare skin chills fast.
The humidex tops 30 on about 66 days a year: muggy days to plan around.
Thirty-year normals hide the storms and the extremes: the hazards page has Chatham’s risks.
Flood & hazards →ECCC’s normals location: Ridgetown
Behind the 1991–2020 normals for Ridgetown are 2 stations, which ECCC combines into one record.
| Distance from the town | 26 km east |
| Station altitude | 206 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Snowfall from | New Glasgow, 47 km |
| Coldest reading, 1991–2020 | −31.9°C |
| Hottest reading, 1991–2020 | 36.0°C |
| Average wind | 12.8 km/h on average, most often from the south-west |
| Next-nearest location | Erieau, 30 km |
How Chatham compares
Compared with 2,611 towns and neighbourhoods of 2,500 or more across Canada; the dots mark the other normals locations in Ontario.
Nearby towns’ climate
Nearby places read from a different ECCC location (places on Chatham’s own would show the same figures). The nearest places to Chatham with figures are 29–50 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Chatham Ridgetown | 27.2°C | −8.2°C | 903 mm |
| Walpole Island 46 29 km · Windsor Riverside | 29.2°C 2.0°C warmer | −6.3°C 1.9°C milder | 935 mm |
| Enniskillen 50 km · Sarnia | 26.5°C 0.7°C cooler | −8.2°C about the same | 871 mm |
Chatham weather by month
Month by month, 1991–2020: the usual high, low and mean, the rain and snow, and the snowfall.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −0.7°C | −8.2°C | −4.5°C | 83 mm | 28 cm |
| February | 0.5°C | −7.7°C | −3.6°C | 61 mm | 22 cm |
| March | 5.6°C | −3.1°C | 1.2°C | 64 mm | 13 cm |
| April | 12.7°C | 2.0°C | 7.4°C | 87 mm | 4 cm |
| May | 19.3°C | 8.1°C | 13.7°C | 83 mm | 0 cm |
| June | 25.0°C | 13.6°C | 19.3°C | 78 mm | 0 cm |
| July | 27.2°C | 15.6°C | 21.4°C | 75 mm | 0 cm |
| August | 26.1°C | 14.6°C | 20.3°C | 74 mm | 0 cm |
| September | 22.7°C | 11.0°C | 16.9°C | 81 mm | 0 cm |
| October | 15.8°C | 5.7°C | 10.8°C | 72 mm | under 1 cm |
| November | 8.4°C | 0.6°C | 4.5°C | 74 mm | 4 cm |
| December | 2.4°C | −4.2°C | −0.8°C | 70 mm | 19 cm |
| Year | 13.7°C | 4.0°C | 8.9°C | 903 mm | 91 cm |
A February here can run from −31.9°C to 19.4°C
February is the least predictable month: about two years in three its average lands within 3.2°C of the normal, −3.6°C. June is the steadiest, within 1.2°C.
Where Chatham’s numbers come from
Averages over 30 years, not a forecast.
- Normals: Environment and Climate Change Canada’s 1991–2020 normals, Ridgetown: the nearest of its locations with every month’s temperatures.
- Other locations: precipitation and snowfall come from the nearest location that publishes all twelve months of them, as named above.
- Comparisons: Canadian towns and neighbourhoods of at least 2,500, each placed by its nearest location (city totals and reserves excluded).
- Not on this page: a sunshine figure (ECCC published none for 1991–2020) and any lapse-rate correction for height, as the town has no elevation here.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Chatham’s climate
How warm does Chatham get in summer?
A normal July afternoon tops out at about 27.2°C, the year’s high point.
How cold does Chatham get in winter?
Deep winter means January, when nights average −8.2°C.
How much rain and snow does Chatham get?
Rain and snow, with snow counted as water, total 903 mm a year; April leads with 87 mm and February trails with 61 mm.
Are these figures for Chatham itself?
Yes: they are ECCC’s 1991–2020 normals for Ridgetown, a location inside Chatham.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Chatham →
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).