THUNDER BAY – May 2, 2025 – If ever there were a forecast that summed up Northern Ontario’s identity crisis in spring, today is it. Thunder Bay starts the day with light rain, but don’t get too cozy with the drizzle—snow is elbowing its way into the forecast before we leap into sunshine and near-20°C highs for the weekend.
As of 6:00 AM at the Thunder Bay Airport, it’s 1.9°C with 96% humidity and a dew point of 1.3°C. Light rain is falling across the city with calm northwest winds at 3 km/h. Visibility remains strong at 24 km, and barometric pressure is on the rise at 101.3 kPa—pointing to improved weather ahead, once the sky figures out what season it’s in.
This morning’s rain is expected to shift into a mix of snow and rain (yes, in May), before tapering off early this afternoon. After that, skies will remain mostly cloudy with a high of 12°C. The UV index reaches a moderate 4—not high enough to fry you, but not invisible either.
For context, May 2 in Thunder Bay has seen it all. The record high was a summery 28.3°C back in 1951, while the coldest ever was -9.4°C in 1963. So, while snow this time of year feels offensive, it’s not exactly unprecedented.
Tonight brings a sharp dip in temperature as skies turn partly cloudy and the mercury drops to -2°C. If you packed away your winter coat too soon, tonight might make you regret that optimistic decision.
Saturday brings an optimistic rebound. After a chilly morning with wind chills near -4, the skies will clear and the temperature will climb quickly to 18°C. Winds will remain light, and the UV index rises to a healthy 6—so sunglasses and sunscreen will be your weekend companions. Saturday night is clear and calm with a mild low of 4°C.
Sunday continues the spring glow-up with full sunshine and a high of 19°C. It’s shaping up to be a perfect day for gardening, lakeside lounging, or taking that winter-worn bike for a spin. Another clear night follows with a low of 4°C.
Monday sticks with the sunshine trend, bringing another high of 18°C and a crystal-clear night dipping to 5°C. Spring may have stumbled out of the gate, but it’s finally catching its stride.
Today’s attire calls for waterproof layers this morning—something that can handle both rain and rogue snowflakes. But keep those sunglasses within reach for the weekend, because it’s about to feel like the seasons got their schedules sorted out at last.
And here’s your Thunder Bay weather trivia for the day: thanks to its location on Lake Superior, Thunder Bay is notorious for “lake-effect confusion”—cooler springs, surprise snow, and fog banks that materialize like magic. But once a high-pressure system settles in, the city transforms into a sun-drenched gem, perfect for soaking in those long-awaited spring rays.
