Lake Superior’s Cool Influence Keeps Thunder Bay Chilly
Thunder Bay, ON – While some Ontario communities are basking in early spring warmth, Lake Superior has other plans for Thunder Bay, keeping the city frosty this Saturday morning. As of 6:00 AM EDT, it’s a brisk -3.2°C under clear skies, and with a northeast breeze at 10 km/h, it feels closer to -7°C thanks to the wind chill.
Don’t be fooled by the sunny start — change is on the way, and it might just come with a snow shovel.
Today’s Outlook: Sunny Start, Showers Possible
Skies are clear early on, but increasing cloudiness is expected this morning. There’s a 40% chance of showers developing this afternoon as a new system moves into the region. Winds will stay light, up to 15 km/h, and the temperature will gradually rise to a high of 8°C. With humidity at 93%, a dew point of -4.2°C, and barometric pressure at 101.9 kPa and falling, Thunder Bay is clearly on the edge of a weather shift.
Visibility is excellent at 24 km, so morning drives or scenic lake views are still in play. The UV index will reach 4, so a bit of sunscreen wouldn’t hurt if you’re out enjoying the clearer skies.
Tonight and Sunday: From Calm to Storm Warnings
Tonight brings partly cloudy skies with fog patches developing overnight, and a low of -1°C. So if you’re out after dark or waking early Sunday, expect some patchy mist along roadways and near the lake.
Sunday, April 13, starts off with a mix of sun and cloud, but it won’t last. Cloud cover increases by midday, followed by a 60% chance of showers by late afternoon. Fog patches from the morning will dissipate, and daytime highs will climb to 11°C — one of the warmest days in the upcoming stretch. The UV index remains moderate at 4.
But hold onto your toque — Sunday night brings a 70% chance of rain or snow, and with temperatures hovering around zero, travel conditions could begin to deteriorate.
Snowfall Advisory Begins Sunday Night
Environment Canada has issued an early heads-up for Sunday night through Tuesday morning (8:00 PM Sunday – 6:00 AM Tuesday), warning of accumulating snow and occasional blowing snow. Roads may become slippery or snow-covered, particularly if left untreated. If you’ve swapped out your snow tires already… you might want to reconsider.
Monday and Beyond: Back to Winter (Briefly)
Monday brings snow or rain, with a high of only +2°C, followed by more snow or rain Monday night, dipping to -2°C. Things start to settle by Tuesday, April 15, with clearing skies and a high of 8°C, and an overnight low of -9°C to remind you that April isn’t finished with frost just yet.
Historic April 12 Weather in Thunder Bay
The record high for this date is a toasty 22.3°C, while the record low sits at -18.9°C — so today’s chilly start is somewhere in the middle, but definitely leaning toward the colder side of the spectrum.
What to Wear?
This is a “dress in layers and bring an umbrella just in case” kind of weekend. You’ll need a warm coat for the early mornings and evenings, and waterproof gear could come in handy by Sunday afternoon. And yes, keep the winter boots by the door — Monday might be slushy.
Thunder Bay Weather Trivia
Did you know? Thunder Bay holds the title for the snowiest city in Ontario, with an average of over 300 cm of snow per year — so one last April blast? Completely on brand.
