Environment Canada is forecasting sunny skies for Sarnia, ON after issuing its forecast at 3:30 PM EDT Monday, May 25, 2026. The agency predicts a high of 28°C on Tuesday, May 26 with a Humidex of 30 and a UV index of 8, making the day noticeably warmer than normal for late May.
Conditions at Sarnia Chris Hadfield Airport at 1:00 PM on Monday, May 25 were recorded as Sunny with a temperature of 21.1°C and visibility of 16 km. No weather alerts are in effect for the Sarnia-Lambton area, and The Weather Network also reports clear conditions with no active alerts as of Monday afternoon.
The forecasted 28°C high is about 6 degrees above the seasonal normal high of 22°C for late May. May climate normals show an average high of 18.7°C and an all-time May record high of 33.3°C, according to ExtremeWeatherWatch. Residents planning time outdoors should note the very high UV index and the elevated Humidex on Tuesday, and take usual sun and heat precautions such as sunscreen and drinking water.
Overall, Environment Canada expects sunny conditions for the start of the week and no alerts are in effect at this time. Residents who want the official details can consult the Environment Canada forecast page for Sarnia for updates and any changes to the outlook.
