It’s a bright and breezy Monday morning in Thunder Bay, where the thermometer is currently reading 8.1°C as of 8:00 AM. With clear skies and visibility stretching a full 32 km, you might be tempted to plan an entire day outside—but don’t be fooled by the fresh start. The barometric pressure is at 100.9 kPa and rising, and some weather drama is brewing.
Humidity sits at 72%, the wind is currently out of the northwest at 4 km/h, but a noticeable change is expected. By this afternoon, winds will shift to the southwest and pick up speed to 30 km/h, gusting up to 50 km/h, sweeping in hazy skies that will thicken into local smoke. It’ll be a scorcher too—the high is forecast to hit 27°C, with a humidex of 32 and a blazing UV index of 9, rated as very high. Don’t leave home without your sunblock, hat, and maybe a respirator if you’re sensitive to smoke.
But that’s not all. This afternoon brings a 30 percent chance of showers and the risk of a thunderstorm, which could stir things up further. So, if you’re planning a lakefront stroll or hitting the trails, consider making it a morning affair.
Tonight, things stay active. Mainly cloudy skies will linger, with a 40 percent chance of showers and a continued risk of thunderstorms. Winds will shift again, this time from the south at 20 km/h, before easing late this evening. Temperatures will dip to a warmish low of 15°C, which may make for some restless, sticky sleep if you’re without air conditioning—and with windows shut against smoke, that might be the case.
Looking ahead to Tuesday, showers are expected, with lingering local smoke in the afternoon. The high will reach a more comfortable 23°C, though the UV index drops to a moderate 3. Tuesday night will bring clearing skies and a crisp low of 8°C.
Mid-week looks like a return to classic Northwestern Ontario weather: sunny and pleasant on Wednesday with a high of 24°C, followed by a clear and cool Wednesday night with a low of 6°C.
If you’re dressing for the day, start light and layer wisely—shorts will feel great by midday, but keep a rain jacket or umbrella close. And with the smoke in the forecast, it’s also a good day to keep outdoor activities limited, especially for anyone sensitive to air quality changes.
Here’s a breezy bit of Thunder Bay trivia: thanks to its location on Lake Superior, Thunder Bay can experience “lake breeze fronts”—natural air-conditioning systems that can drop the temperature dramatically in just minutes. But not today. Today, summer’s flexing its muscles, and even the big lake might not help you cool off.
