Photo: P199 · CC BY-SA 3.0Midwinter lows in Petrolia stay above those of 83% of Canadian towns
Midsummer highs settle at about 26.5°C. Its July heat outdoes that of 65% of Canadian towns. The gap between a January night and a July afternoon is 35°C. Expect about 131 frosty starts a year, days when the air falls to freezing.
These are not Petrolia’s own readings: ECCC keeps no normals there, so the page uses Sarnia, 19 km north-west.
A year in Petrolia at a glance
Each month’s typical high and low, in °C.
What stands out about Petrolia’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Petrolia feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
131 frost days and 124 days above 20°C a year
The frost season runs October to April, and January freezes nearly every night. Some 15 days a year climb past 30°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 871 mm a year
June brings the most rain and snow; February, the least. About 113 days a year bring 1 mm or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
Snowfall: about 112 cm in a normal year
From November to April snow is likely; January is the peak, at about 34 cm.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Petrolia
92% of a year’s heating need falls between October and April. Months averaging under 10°C: November to April.
ECCC sums, over the year, how many degrees each day’s average falls short of 18°C. A house here needs less heating than 86% of Canadian towns.
Living with Petrolia’s climate
Gardening, time outside, winter cold and summer heat, from the 1991–2020 normals.
Afternoons of 17–27°C and nights of at least 8°C arrive in Jun, Jul, Aug and Sep.
Parks & trails →Bitter wind chill, under −20, comes on about 14 days a year.
The normals describe a typical year, not its worst days; the hazards page covers Petrolia’s.
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 | 19 km north-west |
| 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 | Strathroy-Mullifarry, 42 km |
How Petrolia compares
Against the 2,611 Canadian towns and neighbourhoods of 2,500 or more, each read from its own normals location; the dots are the other locations those towns use in Ontario.
Nearby towns’ climate
The nearest places on a normals location of their own: those that share Petrolia’s would only repeat its figures. The nearest places to Petrolia with figures are 22–24 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Petrolia Sarnia | 26.5°C | −8.2°C | 871 mm |
| Dawn-Euphemia 22 km · Ridgetown | 27.2°C 0.7°C warmer | −8.2°C about the same | 903 mm |
| Brooke-Alvinston 23 km · Strathroy-Mullifarry | 27.3°C 0.8°C warmer | −8.5°C about the same | 966 mm |
Petrolia 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 |
Two years in three, February’s average lands within 2.9°C of normal, against the steadier June
The thirty-year records stretch furthest in March: a low of −22.3°C in 2003 and a high of 27.9°C in 2012.
Where Petrolia’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the Canadian Climate Normals, 1991–2020, at Sarnia (the closest location with all twelve months of temperatures).
- Comparisons: every Canadian town and neighbourhood of 2,500 or more, each read from its own nearest location; city totals and reserves are left out.
- Not on this page: hours of sunshine, missing from the 1991–2020 normals, and a height correction: the town has no elevation on file.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Petrolia’s climate
How warm does Petrolia get in summer?
Expect highs near 26.5°C in July, the hottest month on average.
How cold does Petrolia get in winter?
Lows sink to −8.2°C on an average January night.
How much rain and snow does Petrolia 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 Petrolia itself?
Not as such: Sarnia is the nearest normals location, and Petrolia has none.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Petrolia →
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).