Cold Morning, Sunny Day, and Then Comes the Thunder
SIOUX LOOKOUT & PICKLE LAKE, ON – May 10, 2025 – The morning in northwestern Ontario feels more like late winter than mid-May. At 5:00 AM in Sioux Lookout, the temperature is sitting at a crisp -1.1°C with 100% humidity, making it feel even chillier with a wind chill of -2. Winds are light from the north at just 3 km/h, and visibility is excellent at 24 km. The barometric pressure is at a firm 103.0 kPa and rising, signaling a stable but changing atmosphere.
Skies are mainly clear this morning, but don’t get too comfortable. Sunshine will give way to a mix of sun and cloud by the afternoon, and there’s a 30 percent chance of showers sneaking in late today. Highs will climb to a surprisingly pleasant 16°C, a significant rebound from the morning frost. The UV index hits 6, which is high enough to warrant sunglasses and sunscreen if you’ll be out during the sunny breaks.
Thunderstorm Risk Creeps in Tonight
Saturday night keeps the weather mood unpredictable with partly cloudy skies and a 30 percent chance of showers. There’s also a risk of an overnight thunderstorm as a southerly wind picks up to 20 km/h. Expect temperatures to stay well above freezing, dipping only to a low of +5°C.
Sunday Cranks Up the Heat and the Thunder Potential
Sunday might leave you checking the calendar—it’ll feel more like July than May. A high of 27°C is on the way, but with it comes another 30 percent chance of showers and the risk of thunderstorms. Winds will be from the south at 20 km/h before easing off in the morning. Despite the unsettled skies, the UV index remains high at 7, so make sure you’re sun-smart between any cloud breaks.
Sunday night brings cloudy periods and continued chance of showers with a mild low of 15°C.
What to Wear
You’ll need layers for the temperature swing today—mittens in the morning, t-shirt by mid-afternoon. A light rain jacket would be a smart companion both today and tomorrow, just in case a thunderstorm decides to make a dramatic entrance.
Weather Trivia: Sioux Lookout’s Sizzling and Freezing Past
The record high for May 10 in Sioux Lookout was a toasty 29.2°C set in 1991. On the flip side, the record low dipped to -8.0°C in 1975. So, today’s early frost and tomorrow’s 27°C scorcher are both perfectly on brand for this famously wild-weather region.
