A Mild Morning Gives Way to Wet Weather and a Midweek Chill
Forecast for Sunday, April 13, 2025
Thunder Bay woke up under a thick, moody sky this morning, with a calm and cloudy atmosphere dominating the scene. As of 7:00 AM EDT, the temperature at Thunder Bay Airport sat at a crisp -1.8°C with 100% humidity—yep, it’s one of those mornings where the dew point matches the air temperature, giving us that classic early spring fog blanket. Visibility is holding strong at 16 km, and there’s no wind to stir things up just yet, though light breezes up to 15 km/h are expected later today.
The day ahead will stay cloudy, with those fog patches finally calling it quits as the morning progresses. We’re heading for a high of 9°C, though it might feel a bit chillier in the morning with a wind chill sitting at -5°C. The UV index creeps up to a moderate 3—so if the sun peeks out briefly, don’t forget your sunscreen.
As we head into tonight, things take a wetter turn. There’s a 60% chance of showers this evening, with steadier rainfall beginning after midnight. Expect about 10 mm of rain overnight and temperatures hovering around +2°C. Perfect weather to fall asleep to the sound of raindrops pattering on your windows.
Monday Turns Moody: Rain, Snow, and Gusty Winds
Thunder Bay residents should prepare for a mixed bag on Monday, April 14th. Rain will greet the morning hours, but don’t get too cozy—it’s expected to switch over to snow mixed with rain near noon. Inland areas might see up to 5 cm of snow, while the total precipitation could reach 10 to 20 mm. Winds will pick up as well, shifting to the northwest at 30 km/h with gusts up to 50 km/h by late morning. Temperatures will stay steady near +2°C through the day, and the UV index will dip to a low 1.
Monday night stays snowy, with periods of snow and some local blowing snow keeping visibility in check. Winds will remain strong and temperatures will dip to -2°C, making for a cold and breezy night.
Tuesday and Wednesday Bring a Little Sunshine—And a Lot of Chill
Tuesday, April 15, brings a bit of variety with a mix of sun and cloud and a 30% chance of flurries. The high reaches +5°C, which sounds almost balmy after Monday’s moody mix. Clear skies return by Tuesday night, but so does a blast of cold air, with overnight lows dropping to a frosty -9°C.
Wednesday, April 16, brings a bright and sunny day with a high near +4°C. But clouds start creeping back in by nightfall, along with a 30% chance of rain showers or flurries, and a low of -4°C.
What to Wear in Thunder Bay This Week
Layer up and keep the waterproof gear within reach—Sunday may be dry-ish, but tonight kicks off several days of precipitation. A waterproof jacket, insulated footwear, and maybe a toque for those chilly mornings will serve you well. Don’t ditch the winter wear just yet—Tuesday and Wednesday mornings are especially nippy!
Thunder Bay Weather Trivia
Did you know? Thunder Bay holds the record for the highest temperature ever recorded in Ontario during April—33.3°C on April 23, 1990! That’s hard to believe when we’re dodging snowflakes mid-April, isn’t it?
Historic High for April 13 in Thunder Bay: 24.0°C (1977)
Historic Low for April 13 in Thunder Bay: -18.9°C (1950)
