FORT FRANCES, ON — Northwestern Ontario is heating up in a big way as Environment Canada issues its first heat warning of the season for Fort Frances, Atikokan, Shebandowan, and Nigigoonsiminikaaning First Nation. With daytime highs reaching the low 30s and nighttime temperatures stubbornly staying above 20°C, residents are being urged to take heat precautions seriously.
Historically, Fort Frances has experienced wide temperature swings on May 11—from a chilly -3.2°C to a sizzling 33.0°C. With this week’s highs threatening that upper record, 2025 may go down as one of the hottest starts to May on record.
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The temperature at 5:00 AM Monday sat at a mild 10.0°C, but don’t be fooled—humidity levels remain low at 35%, and barometric pressure at 101.7 kPa is falling, signaling unstable and warming air masses. Winds out of the east at 20 km/h will swing southwest by the afternoon, gusting up to 50 km/h as skies clear and the UV index climbs to a dangerous 8—classified as “very high.”

Fort Frances is forecasted to be the hottest spot in Northwestern Ontario this week, peaking at a blazing 32°C Monday. Heat will persist overnight with a minimum of 20°C, offering little relief for those without air conditioning. Winds will continue to intensify on Tuesday, gusting up to 60 km/h, with yet another high of 31°C under unrelenting sunshine.
By Wednesday, a slight reprieve comes in the form of cloud cover and a modest 30% chance of showers, though daytime highs remain around 30°C. The real cooldown begins Thursday with increased rainfall and a daytime high of 24°C. Friday brings a dramatic drop to 14°C—nearly 20 degrees cooler than Monday’s high—with lingering showers and overcast skies.
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