Photo: Fralambert · CC BY-SA 4.0Wet weather: 1,178 mm of rain and snow a year falls on Chertsey, more than on 88% of Canadian towns
Sunny July days climb to about 26.6°C. Its January nights bite harder than in 75% of Canadian towns. Seasons differ by 43°C, from the coldest nights to the warmest afternoons. Long walks are most pleasant from June to September, when afternoons reach 21–27°C.
Borrowed figures: Chertsey has no normals station, so these come from L'Assomption, 46 km south-east.
A year in Chertsey at a glance
Each month’s typical high and low, in °C.
What stands out about Chertsey’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Quebec beside it.
What a year in Chertsey feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
161 frost days and 119 days above 20°C a year
The frost season runs October to May, and January freezes nearly every night. On about 24 nights a year the air falls below −20°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
Rain and melted snow: about 1,178 mm a year
October is the wettest month and February the driest. On about 143 days a year, 1 mm or more falls.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
L'Assomption publishes no full year of precipitation or snowfall, so these figures, and the snow below, come from Lachute, 59 km away.
218 cm of snow in a typical year
Snow falls from October to April, most of all in January (about 56 cm).
Snowfall by month
Centimetres
Heating a home in Chertsey
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
A heating degree day is one degree of shortfall below 18°C for one day, summed over the year.
Living with Chertsey’s climate
What the normals mean for a garden, a day outside and the depth of winter.
The comfortable months for a day outside, highs of 17–27°C and nights of 8°C or more: Jun, Jul, Aug and Sep.
Parks & trails →Expect around 44 days a year when the wind chill sinks below −20.
Muggy heat with a humidex over 30 arrives on about 49 days a year.
Thirty-year normals hide the storms and the extremes: the hazards page has Chertsey’s risks.
Flood & hazards →ECCC’s normals location: L'Assomption
L'Assomption is one of the 450 places where ECCC publishes 1991–2020 normals.
| Distance from the town | 46 km south-east |
| Station altitude | 21 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Precipitation from | Lachute, 59 km |
| Coldest reading, 1991–2020 | −40.0°C |
| Hottest reading, 1991–2020 | 36.2°C |
| Average wind | 10.0 km/h on average, most often from the south-west |
| Next-nearest location | St-Jovite, 52 km |
How Chertsey compares
Compared with 2,611 towns and neighbourhoods of 2,500 or more across Canada; the dots mark the other normals locations in Quebec.
Nearby towns’ climate
The nearest places on a normals location of their own: those that share Chertsey’s would only repeat its figures.
Chertsey 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 | −5.9°C | −16.0°C | −10.9°C | 97 mm | 56 cm |
| February | −4.0°C | −14.8°C | −9.4°C | 72 mm | 47 cm |
| March | 1.8°C | −8.3°C | −3.2°C | 74 mm | 34 cm |
| April | 10.8°C | 0.1°C | 5.5°C | 100 mm | 8 cm |
| May | 19.2°C | 7.2°C | 13.2°C | 89 mm | 0 cm |
| June | 24.3°C | 12.4°C | 18.4°C | 111 mm | 0 cm |
| July | 26.6°C | 14.8°C | 20.7°C | 112 mm | 0 cm |
| August | 25.5°C | 13.7°C | 19.6°C | 104 mm | 0 cm |
| September | 21.1°C | 9.2°C | 15.2°C | 114 mm | 0 cm |
| October | 13.0°C | 3.2°C | 8.1°C | 120 mm | 2 cm |
| November | 5.4°C | −2.7°C | 1.3°C | 93 mm | 17 cm |
| December | −1.9°C | −10.2°C | −6.1°C | 94 mm | 53 cm |
| Year | 11.3°C | 0.7°C | 6.0°C | 1,178 mm | 218 cm |
Two years in three, January’s average lands within 3.1°C of normal, against the steadier June
Records from 1991 to 2020: no month spans more than March, between −29.5°C (1992) and 26.0°C (2012).
Where Chertsey’s numbers come from
Averages over 30 years, not a forecast.
- Normals: ECCC’s 1991–2020 Canadian Climate Normals for L'Assomption, the nearest location with a full year of temperatures.
- Other locations: ECCC blanks a month that fails its completeness rule, so the precipitation or snowfall here comes from the next location with all twelve months.
- Comparisons: the 2,500-plus towns and neighbourhoods of Canada, each read from its closest normals location; whole cities and reserves aren’t counted.
- 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 Chertsey’s climate
How warm does Chertsey get in summer?
On a normal day in July the thermometer climbs to 26.6°C, the warmest of the year.
How cold does Chertsey get in winter?
January nights average −16.0°C, the coldest of the year.
How much rain and snow does Chertsey get?
About 1,178 mm a year, rain and melted snow together. October is the wettest month (120 mm) and February the driest (72 mm).
Are these figures for Chertsey itself?
The figures are ECCC’s for L'Assomption; Chertsey has no normals station.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Chertsey →
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).