Sarnia Weather & Climate

Canada

Sarnia sees feels-like daytime highs peak around 30.1°C in July and nighttime lows bottom out near -8.3°C in January. September is the wettest month (~67 mm), while February is the driest (~17 mm). For sunshine, August leads with about 66% clear skies.

Best time to visit Sarnia

Based on mild feels-like temperatures and low rain chances, the most comfortable months are June, September, and August — expect around 16.727°C with roughly 33% chance of rain on a given day in June.

Sarnia climate by month

MonthLow / High °CRain %RainfallClear skiesWind
January-8.3° / -3.1°8%18 mm34%22.1 kph
February-7.8° / -1.1°7%17 mm37%21.3 kph
March-3.4° / 4.4°15%31 mm43%20.9 kph
April3.5° / 12.4°26%50 mm46%19.9 kph
May10° / 20.3°31%59 mm49%17.5 kph
June16.7° / 27°33%62 mm56%15.3 kph
July19.6° / 30.1°33%61 mm64%14 kph
August18.5° / 28.9°33%64 mm66%14 kph
September14.4° / 24.4°32%67 mm63%16 kph
October7.2° / 15.5°27%57 mm56%18.8 kph
November0.6° / 6.9°20%45 mm45%20.7 kph
December-5° / 0.1°14%29 mm38%21.8 kph

Feels-like temperatures from long-term historical data; ☀ marks the most comfortable months (mild temperatures, low rain).

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