Thunder Bay’s Sky Plays Nice—Until Thursday Night
Thunder Bay is starting the day on a very chilly note, with the thermometer reading -5.7°C as of 6:00 AM at the airport. With a light northwest breeze at 4 km/h, it feels like -8°C. Humidity is near saturation at 99%, and while that might sound oppressive, it just adds to the damp chill of a near-freezing morning. Visibility is excellent at 24 km, and the barometric pressure sits at 102.3 kPa—but it’s falling, which suggests changes are on the way.
The forecast for today brings a classic case of “don’t get used to it.” Skies will remain mainly sunny this morning before cloud cover rolls in around noon. Morning fog patches will lift, and winds will shift from calm to southeast at 20 km/h late this morning. Despite the sunshine, it’ll still feel cool, with a daytime high of only +5°C. The UV index, however, is expected to reach 6—considered high—so sun protection is a good idea even if you’re still wearing gloves.
Tonight brings increasing cloudiness and a 30% chance of showers, with an overnight low of +1°C. Fog is possible again overnight, so visibility may dip into the early morning hours on Thursday.
Thursday’s forecast offers a mix of sun and cloud with a 40% chance of showers throughout the day. Winds will turn east at 20 km/h by afternoon, helping bump the high up to a milder 11°C. The UV index remains at 6, meaning even the filtered sun can do damage if you’re outdoors for long. Thursday night turns a little wintry once more, with a 60% chance of rain showers or flurries as the temperature drops to -1°C.
Friday stays grey with a 30% chance of more showers or flurries, and the temperature struggles to reach a high of just 6°C. That night will bring some clearing but another cold low of -5°C.
Saturday, however, gives us a well-earned reprieve: a mix of sun and cloud, a high of 12°C, and—best of all—clear skies and a low around zero for Saturday night.
In Thunder Bay’s weather history, the record high for April 30 was a delightful 25.3°C in 1998, while the record low was a brisk -10.6°C back in 1967. So this morning’s -6°C puts us on the colder side of normal but still far from the chilliest on record.
Wardrobe Recommendation: It’s a full-layer day in the Bay. Bundle up with a wind-resistant coat and gloves this morning, then shed a layer or two by midday. Keep the umbrella handy tonight, and maybe prep the windshield scraper for Friday morning—just in case.
Thunder Bay Weather Trivia:
Thunder Bay holds the record for the coldest May temperature in Ontario: -10.6°C on May 7, 1967. So yes, spring likes to take its time here.
