Chilly Thanksgiving may bring hint of snow to southern Ontario

A raw, chilly holiday is on tap for most communities across southern Ontario

A noticeably chilly pattern will descend on the Great Lakes through Thanksgiving on Monday, bringing the region some of the coldest temperatures we’ve seen since spring.

This pattern will also bring rain, gusty winds, and even a touch of snow for some folks at higher elevations. Ready or not, October snows can happen!

DON’T MISS: Ready for the chill? Southern Ontario's coldest day since April looms

There is a higher level of uncertainty on precipitation coverage across southern Ontario through Monday due to the uncertainty of a developing low-pressure system and being on the outer fringe of a storm track. However, make sure you are dressed warmly if you're planning on venturing outdoors, even if it's just to get to your parked vehicle.

Monday and Tuesday: Chilliest days since April

Precipitation that started on Sunday will linger into the day Monday. We could even see a wintry mix along the Highway 401 corridor near Brockville and Cornwall early Monday morning as temperatures hover just a few degrees above zero.

The risk for precipitation will diminish across the Greater Toronto Area (GTA) as the low-pressure system moves east, but continues to pester eastern Ontario.

MUST SEE: A ‘weak’ La Niña is likely as Canada heads into this winter

Northerly winds will help keep temperatures unseasonably cold starting on Monday.

Content continues below
Ontario wind gustsMonday morning

Temperatures will struggle to reach the double digits throughout southern Ontario, with even chillier readings expected beneath more organized precipitation across eastern portions of the province.

The last time we saw single-digit highs across southern Ontario include:

  • April 24 - Windsor

  • April 25 - Toronto, Hamilton

  • April 25 - Kingston

  • April 30 - Ottawa

Ontario's last single-digit highs in 2024

If Toronto fails to hit 10°C on Monday or Tuesday, it'll be our first day mired in the single digits since April 25. Ottawa is looking at its coldest day since April 5.

By late Monday, we’ll see lake-effect showers snaking down from Georgian Bay and Lake Huron, providing some scattered precipitation through Tuesday. This will bring a risk for mixed precipitation for some higher-elevations areas on the escarpment and toward cottage country, where some flurries are expected heading into Tuesday.

Ontario forecast conditions Tuesday morning

Right now, it looks like the Dundalk Highlands (elevation: 526 metres), north of Orangeville and Algonquin, are at risk for a coating of snowfall beginning early Tuesday.

Regions north of Orangeville along HIghway 10, including Shelburne, are at the highest risk of seeing their first light accumulating snowfall of the season.

Content continues below

Temperatures hovering a couple of degrees above freezing through the overnight hours across higher terrain mean there is uncertainty in precipitation type, although it is unlikely we’ll see significant snowfall totals anywhere across southern Ontario.

Stay with The Weather Network for all the latest on conditions across Ontario.

Header image courtesy of Pat Grew.

WATCH: La Niña expected to affect winter in Canada, here's what that means