Mostly cloudy skies hit Thunder Bay on Saturday , with light morning showers possible . The lake keeps waterfront chill noticeable while clouds stick around. By Sunday, sun takes over as inland heat grows . Lake air stays cooler longer than spots farther from the water . Monday brings notable warm-up inland as the heat wave peaks away from Superior. Lakefront areas see relief while inland spots bake. Local forecasters issued this outlook on July 12, 2026. A sunny Sunday follows the week’s damp start.