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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Toronto Post Weather Desk. Data from Environment and Climate Change Canada and other national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
The live forecast above shows Sarnia’s current conditions and today’s high-low range. Expect a daytime high near 24°C and an overnight low around 16°C, with a 40% chance of afternoon showers — typical for late summer along the St. Clair River.
What is the Sarnia weather outlook for this week?
Tuesday and Wednesday bring a mix of sun and cloud, with highs holding near 22–25°C and a slight chance of isolated thunderstorms midweek. By Thursday, a cold front may drop temperatures to 18°C, with gusty northwest winds up to 30 km/h. The Canada weather hub tracks these shifts for the region.
How does Lake Huron affect Sarnia’s weather?
Lake Huron moderates Sarnia’s climate, keeping spring and fall milder than inland areas. The lake also fuels lake-effect cloud bands in late autumn, but for now, the weather warning page is clear of any active alerts. For real-time tracking, check the sarnia weather radar and sarnia weather radar hourly updates.
What is the best source for Sarnia weather hourly updates?
Environment and Climate Change Canada provides official hourly forecasts for Sarnia. The sarnia weather hourly data is updated every hour and includes temperature, wind, and precipitation probability.
Where can I see a Sarnia weather map?
The sarnia weather map on The Weather Network shows radar, satellite, and temperature overlays. It’s useful for tracking approaching systems from Lake Huron or the U.S. side of the St. Clair River.
Is there a 14-day forecast for Sarnia?
Yes, the sarnia weather 14 day outlook is available from Environment Canada. Accuracy decreases beyond 7 days, but it gives a general trend for temperature and precipitation patterns.