Dorchester gets fewer frosts than 75% of Canadian towns
Expect July afternoons of about 26.6°C. Summer afternoons here are warmer than in 70% of Canadian towns. Precipitation barely changes with the seasons; September and February sit close. Plan for rain or snow on about 128 days a year, the days with 1 mm or more.
ECCC publishes no normals for Dorchester itself; the figures are those of London, 6.9 km west.
A year in Dorchester at a glance
Each month’s typical high and low, in °C.
What stands out about Dorchester’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Dorchester feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
About 139 frosts and 128 warm days a year
Frost comes from October to May; in January almost every night freezes. About 11 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 962 mm of rain and snow a year
Rain and snow by month
Millimetres
About 152 cm of snow a year
The snow season runs October to April; January brings the most, about 43 cm.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
ECCC’s London normals leave snowfall out; the figures here come from Strathroy-Mullifarry, 48 km away.
Heating a home in Dorchester
92% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
The total grows by a degree for every degree a day’s mean sits under 18°C. A house here needs less heating than 79% of Canadian towns.
Living with Dorchester’s climate
Gardening, time outside, winter cold and summer heat, from the 1991–2020 normals.
A normal year gives the garden about 165 frost-free days, roughly 3 May to 16 October.
For long days outdoors, Jun, Jul, Aug and Sep bring highs of 17–27°C and lows of 8°C or more.
Parks & trails →On some 18 days a year the wind chill drops past −20; mitts and a scarf earn their place.
Roughly 55 days a year feel hotter than 30 once humidity is counted.
Extremes don’t show in averages: floods, wildfire smoke and ice storms are on Dorchester’s hazards page.
Flood & hazards →ECCC’s normals location: London
ECCC builds the London normals from 3 stations’ records over 1991–2020, joined where one replaced another.
| Distance from the town | 6.9 km west |
| Station altitude | 278 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Snowfall from | Strathroy-Mullifarry, 48 km |
| Coldest reading, 1991–2020 | −29.1°C |
| Hottest reading, 1991–2020 | 37.0°C |
| Average wind | 14.0 km/h on average, most often from the west |
| Next-nearest location | Delhi, 45 km |
How Dorchester compares
Placed among 2,611 Canadian towns and neighbourhoods of 2,500+, each on its nearest normals location; each dot is another location used in Ontario.
Nearby towns’ climate
Places around Dorchester whose figures come from another normals location. Dorchester has few close neighbours with figures, so the list reaches 23–38 km out.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Dorchester London | 26.6°C | −9.1°C | 962 mm |
| South-West Oxford 23 km · Delhi | 27.5°C 0.9°C warmer | −8.9°C about the same | 965 mm |
| Oneida 41 35 km · Strathroy-Mullifarry | 27.3°C 0.7°C warmer | −8.5°C 0.6°C milder | 966 mm |
Dorchester weather by month
Average daily high and low, mean temperature, rain and snow (as water) and snowfall by month, 1991–2020.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −1.6°C | −9.1°C | −5.4°C | 79 mm | 43 cm |
| February | −0.6°C | −9.0°C | −4.8°C | 63 mm | 32 cm |
| March | 4.6°C | −4.5°C | 0.1°C | 67 mm | 20 cm |
| April | 12.2°C | 1.4°C | 6.8°C | 89 mm | 5 cm |
| May | 19.3°C | 7.7°C | 13.5°C | 89 mm | under 1 cm |
| June | 24.4°C | 13.2°C | 18.8°C | 86 mm | 0 cm |
| July | 26.6°C | 15.3°C | 21.0°C | 81 mm | 0 cm |
| August | 25.7°C | 14.4°C | 20.1°C | 67 mm | 0 cm |
| September | 22.1°C | 10.5°C | 16.3°C | 93 mm | 0 cm |
| October | 14.7°C | 5.0°C | 9.9°C | 83 mm | 2 cm |
| November | 7.5°C | −0.3°C | 3.6°C | 88 mm | 13 cm |
| December | 1.4°C | −5.2°C | −2.0°C | 79 mm | 37 cm |
| Year | 13.0°C | 3.3°C | 8.2°C | 962 mm | 152 cm |
From year to year, February moves by 3.0°C, more than any month, and June least
Over 1991–2020, March saw both −25.6°C (2003) and 27.2°C (2012), the widest span of any month.
Where Dorchester’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the closest ECCC location with twelve months of temperature normals, London, 1991–2020.
- Other locations: a location missing months of precipitation or snow is filled from the nearest that has them all, never mixed month by month.
- Comparisons: a pool of Canadian towns and neighbourhoods of 2,500 or more, read alike; whole cities and reserves stay out of it.
- Not on this page: sunshine (no 1991–2020 normals exist for it) and any altitude adjustment, since there is no elevation for the town itself.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Dorchester’s climate
How warm does Dorchester get in summer?
Midsummer means July, with afternoons near 26.6°C on a typical day.
How cold does Dorchester get in winter?
Midwinter means January, when a typical night reaches −9.1°C.
How much rain and snow does Dorchester get?
Count on roughly 962 mm a year, heaviest in September (93 mm) and lightest in February (63 mm).
Are these figures for Dorchester itself?
They are borrowed from London, the nearest place to Dorchester where ECCC publishes 1991–2020 normals.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Dorchester →
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).