A Chilly Morning Sets the Stage for a Glorious Weekend Warm-Up
THUNDER BAY, ON – May 10, 2025 – Thunder Bay greets the weekend with calm, crisp air and mostly clear skies. At 6:00 AM, temperatures are hovering at 3.2°C, with humidity sitting at 77% and a gentle north-northwest breeze at 4 km/h. Visibility is excellent—an impressive 32 km—so it’s a picture-perfect morning if you’re up early to enjoy the sunrise. The barometric pressure is on the rise at 102.7 kPa, hinting at fair weather dominance ahead.
Sunshine will take the spotlight throughout Saturday, with temperatures climbing to a high of 13°C—still a touch cool, but pleasant under those golden rays. The UV index sits at 7, so if you’re heading outdoors, don’t skip the sunscreen.
Showers Possible Tonight, But Only Briefly
Clear skies will persist through the early evening before a 30 percent chance of showers rolls in overnight. Temperatures will dip to a cool but manageable low of +3°C, so while you may not need the furnace, it’s still jacket weather if you’re out after dark.
Sunday Brings Spring in Full Bloom
Sunday shapes up to be the true winner of the weekend. Expect a mix of sun and cloud in the morning with a lingering 30 percent chance of showers, but those clouds are expected to clear later in the afternoon. The mercury jumps to a much more springlike 22°C, with a continued UV index of 7—great news for patio season fans. Sunday night will be clear with a mild low of 11°C.
Monday Turns Up the Heat
Monday will feel more like summer than spring, with full sunshine and a high of 26°C. Perfect weather for yard work, hiking, or enjoying the shores of Lake Superior—just be ready to break a sweat. Monday night stays clear with a low of 9°C.
What to Wear
Today calls for layers: start with a warm jacket this morning and shed as the sun takes over. By Sunday afternoon and certainly Monday, you’ll be switching to T-shirts, light clothing, and sunglasses. A rain jacket might come in handy overnight or early Sunday, just in case those brief showers show up.
Weather Trivia: Thunder Bay’s May Extremes
Thunder Bay is no stranger to spring’s wild mood swings. The record high for May 10 sits at a warm 28.2°C, recorded in 1987, while the coldest was a frosty -7.8°C in 1960. This weekend’s high of 26°C on Monday? It’s giving those historical numbers a run for their money.
