Sioux Lookout Weather Forecast – A Breezy, Bright Midweek with Frosty Nights
Sunshine Wins the Day, but Morning Chill Lingers
Sioux Lookout, ON – Wednesday, May 21, 2025: It’s a cool start to a sunny day in Northwestern Ontario, where Sioux Lookout is waking up to a temperature of 5.2°C under mostly cloudy skies, as observed at 5:00 AM from Sioux Lookout Airport. The air has a bite to it this morning, thanks to humidity at 57% and an east wind blowing at 15 km/h, gusting up to 32 km/h. The barometric pressure sits at 102.1 kPa, but it’s falling, hinting at a change in weather coming soon — though not before we enjoy a couple of great spring days.
Today’s forecast delivers a healthy dose of sunshine, with skies expected to clear fully as the morning progresses. Winds will pick up to 20 km/h out of the east, with gusts reaching 40 km/h, giving your baseball cap a workout. Temperatures will climb to a high of 16°C, making it a great day to spend some time outdoors. And don’t forget — the UV index is 7, which is considered high, so sun protection is a must if you plan to soak in the rays.
Clear and Cool Tonight – With a Side of Frost
Tonight, skies remain clear, which is great for stargazers, but the air will turn chilly quickly. Winds will shift to the northeast at 20 km/h, becoming light later in the evening. The temperature drops to +2°C, and there is a risk of frost, so gardeners should keep a watchful eye on any tender plants.
Thursday Brings Clouds and a Breezy Twist
Thursday sees a shift in the skies with increasing cloudiness and north winds picking up to 20 km/h, gusting again to 40 km/h. The high will reach 15°C, still quite comfortable, but with more cloud cover and less warmth than today. The UV index remains strong at 6, so even with a few clouds, it’s still important to cover up or lather on that SPF.
Thursday night clears out again, and temperatures dip to +2°C with continued frost risk for the overnight hours.
A Sunny Friday Awaits
Friday returns us to sunny skies and a high of 16°C, continuing the trend of calm, cool, and clear spring days. Friday night stays clear as well with a low around +3°C, and thankfully, less risk of frost.
What to Wear?
Today’s fashion forecast calls for layers — something to fight off the morning chill and wind, with lighter options underneath for when the sun does its thing. A windbreaker or light jacket is a solid pick. Sunglasses and sunscreen are also key players, especially with that UV index pushing 7.
Historic Temperatures for May 21
Sioux Lookout has seen its fair share of spring swings. The record high for this date is a summery 30.5°C, while the record low was a shivery -6.1°C. Today sits comfortably in the safe zone — no record breakers, but no complaints either.
Sioux Lookout Weather Trivia
Did you know Sioux Lookout is affectionately known as the “Hub of the North”? With its central location and sunny skies like today’s, it’s the perfect pit stop between winter’s chill and summer’s heat. Oh, and the town boasts over 2,000 hours of sunshine per year — that’s more than Vancouver!
