Photo: Bhazzard at English Wikipedia · Public domainMidwinter lows in Corunna stay above those of 83% of Canadian towns
Sunny July days climb to about 26.5°C. June is the wettest month, February the driest. Its July heat outdoes that of 65% of Canadian towns. An umbrella or a shovel earns its place on about 113 days a year with 1 mm or more.
The nearest ECCC normals location to Corunna is Sarnia, 23 km north-east, and every figure on this page is its.
A year in Corunna at a glance
Each month’s typical high and low, in °C.
What stands out about Corunna’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Corunna feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
About 131 frosts and 124 warm days a year
The frost season runs October to April, and January freezes nearly every night. Heat of 30°C or more comes on about 15 days a year.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
Rain and melted snow: about 871 mm a year
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
Snowfall: about 112 cm in a normal year
The snow season runs November to April; January brings the most, about 34 cm.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Corunna
92% of a year’s heating need falls between October and April. Months averaging under 10°C: November to April.
A heating degree day is one degree of shortfall below 18°C for one day, summed over the year. Homes here need less heating than 86% of Canadian towns.
Living with Corunna’s climate
The averages read for the garden, the outdoors and the coldest and hottest days.
Mild days and mild nights together (17–27°C by day, 8°C or more at night) belong to Jun, Jul, Aug and Sep.
Parks & trails →About 14 days a year bring a wind chill under −20, when bare skin chills fast.
Thirty-year normals hide the storms and the extremes: the hazards page has Corunna’s risks.
Flood & hazards →ECCC’s normals location: Sarnia
Sarnia is a composite: ECCC joins 4 stations’ readings to make its 1991–2020 normals.
| Distance from the town | 23 km north-east |
| Station altitude | 181 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Coldest reading, 1991–2020 | −28.0°C |
| Hottest reading, 1991–2020 | 37.9°C |
| Average wind | 15.0 km/h on average, most often from the south |
| Next-nearest location | Ridgetown, 63 km |
How Corunna 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
Nearby places read from a different ECCC location (places on Corunna’s own would show the same figures). The nearest places to Corunna with figures are 30–49 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Corunna Sarnia | 26.5°C | −8.2°C | 871 mm |
| Walpole Island 46 30 km · Windsor Riverside | 29.2°C 2.7°C warmer | −6.3°C 1.9°C milder | 935 mm |
| Dawn-Euphemia 36 km · Ridgetown | 27.2°C 0.7°C warmer | −8.2°C about the same | 903 mm |
| Brooke-Alvinston 47 km · Strathroy-Mullifarry | 27.3°C 0.8°C warmer | −8.5°C about the same | 966 mm |
Corunna 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 | −0.9°C | −8.2°C | −4.6°C | 57 mm | 34 cm |
| February | 0.0°C | −7.9°C | −4.0°C | 48 mm | 20 cm |
| March | 5.0°C | −3.7°C | 0.6°C | 57 mm | 22 cm |
| April | 11.9°C | 1.5°C | 6.7°C | 79 mm | 4 cm |
| May | 18.7°C | 7.4°C | 13.1°C | 85 mm | 0 cm |
| June | 24.0°C | 13.0°C | 18.6°C | 93 mm | 0 cm |
| July | 26.5°C | 16.0°C | 21.3°C | 80 mm | 0 cm |
| August | 25.5°C | 15.3°C | 20.4°C | 71 mm | 0 cm |
| September | 22.2°C | 11.3°C | 16.7°C | 84 mm | 0 cm |
| October | 15.4°C | 6.0°C | 10.7°C | 78 mm | 1 cm |
| November | 8.0°C | 0.4°C | 4.2°C | 80 mm | 7 cm |
| December | 2.1°C | −4.4°C | −1.2°C | 60 mm | 25 cm |
| Year | 13.2°C | 3.9°C | 8.5°C | 871 mm | 112 cm |
February varies most from one year to the next (2.9°C), June least
Records from 1991 to 2020: no month spans more than March, between −22.3°C (2003) and 27.9°C (2012).
Where Corunna’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the 1991–2020 normals from ECCC for Sarnia, its nearest location with complete temperatures.
- 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: 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 Corunna’s climate
How warm does Corunna get in summer?
The warmest month is July, when afternoons average 26.5°C.
How cold does Corunna get in winter?
In January, the coldest month, the typical low is −8.2°C.
How much rain and snow does Corunna get?
Rain and snow add up to about 871 mm of water a year; June brings the most (93 mm), February the least (48 mm).
Are these figures for Corunna itself?
Only indirectly: the readings are made at Sarnia, outside Corunna.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Corunna →
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).