Thunder Bay Weather Outlook – Cool Mornings, Mild Afternoons, and Sunshine Just Around the Corner
Cloudy but Calm This Morning, With a Glimmer of Rain Later
Thunder Bay, ON – Saturday, May 24, 2025: The city is waking up under cloudy skies and cool conditions this morning, with a temperature of 5.3°C at 6:00 AM as recorded at Thunder Bay Airport. The air is nearly saturated at 95% humidity, and with a dew point of 4.6°C, there’s a gentle dampness to the morning chill. Winds are light from the west at 6 km/h, and visibility is excellent at 32 km — a promising sign for anyone heading out early. Pressure is on the rise at 102.4 kPa, hinting at improving weather just over the horizon.
The forecast for today calls for mainly cloudy skies with a 30% chance of showers late this afternoon. While not a washout, it’s wise to keep an umbrella nearby if you’re planning to be out and about later today. The high will reach 15°C, mild and manageable, though cloud cover may keep things feeling a bit cooler than the number suggests. The UV index sits at 6, which is considered high — so sun protection is still necessary, even through the clouds.
Clearing Tonight with a Mild, Comfortable Low
Tonight, skies will become partly cloudy, with a low around +5°C. It’s a great night for a backyard fire or a quiet evening stroll — no frost risk, and no rain in sight once the clouds thin.
Sunday Brings a Big Boost in Brightness
Sunday sees the real shift — expect a mix of sun and cloud in the morning, clearing by late morning, and turning into a bright, warm afternoon. The high will reach 19°C, ideal for outdoor plans, hikes, or lakeside relaxation. The UV index rises to 7, so don’t forget the sunscreen, especially if you’re out between late morning and mid-afternoon. Sunday night brings cloudy periods and a low of +4°C.
This is the perfect kind of weather for grilling and barbecue. Ribs are always a favourite.
Monday Keeps the Streak Going
Monday continues the pleasant trend with a mix of sun and cloud and a high of 20°C. It’s the perfect forecast to start the new week on the right foot. Monday night will be partly cloudy with a low again around +4°C — calm, cool, and peaceful.
What to Wear?
This morning calls for a jacket or light sweater, and you’ll want to keep that handy into the afternoon thanks to lingering cloud cover. If you’re outdoors later in the day or Sunday, sunglasses, sunscreen, and a lighter layer underneath are ideal — spring in Thunder Bay is all about flexibility!
Historic Temperatures for May 24
Thunder Bay has seen some swings on this date — the record high is a summery 30.2°C, while the record low dropped to -3.7°C. Today’s forecast lands right in the spring sweet spot — no extremes, just classic Northwestern Ontario springtime.
Thunder Bay Weather Trivia
Did you know Thunder Bay is one of Canada’s top spots for year-round sunrises over water? Thanks to its location on the north shore of Lake Superior, the city boasts stunning early morning views — especially after a morning like today, when clouds give way to sunshine. Sunday’s forecast is shaping up perfectly for just such a show.
