Cool weather arriving in the Maritimes this weekend with autumn equinox

An undated image of a cold blue icy maple leaf with frosted grass in the background. (File photo/Jamie Farrant/GettyImages)

Following a cold front that brought scattered showers to the Maritimes Friday, cool, dry air is moving in from the north bringing risk of patchy frost to parts of the Maritimes Friday and Saturday night.

Frost advisories

Environment Canada has Frost Advisories posted across northern and western areas of New Brunswick Friday.

The combination of clearing sky, easing wind and low temperatures that could dip between -1 and 4 C is a near perfect setup for some mid-September frost. The risk will be highest in low lying areas and valleys. If you live in an area under an advisory and have some temperature sensitive plants, it’s a good night to cover them up or bring them inside.

Brisk nights

It is common for the second night after a passing cold front to be the coolest. That will be the case this weekend.

Overnight temperatures Saturday into Sunday morning could fall into the low-to-mid single digits for a large part of the Maritimes. Some low temperatures in western New Brunswick could fall a degree or two below freezing.

Alongside the risk of frost in New Brunswick early Sunday, I’d include a risk for interior areas of Nova Scotia and the lowest lying areas in western Prince Edward Island.

Low temperatures Sunday night into Monday morning will generally increase a few degrees. Parts of New Brunswick may still need to monitor frost advisories.

Early fall feel

Some appropriately brisk temperatures arrive in the Maritimes this weekend ahead of the Autumnal Equinox at 3:19 p.m. on Monday.

Expect chilly temperatures Saturday and Sunday morning. High temperatures on Saturday afternoon will be mostly in the mid-teens, slightly lower than seasonal expectations. Afternoon high temperatures will be in the high-teens and low-twenties on Sunday, consistent with mid-September averages.

A high-pressure system centred over the region this weekend means the nights will be clear and the days mostly sunny. Some broken cloud cover is expected to move into Cape Breton on Saturday from the Gulf of St. Lawrence accompanied by a low chance of spotty showers.

The next chance of showers arrives in the Maritimes around Tuesday or Wednesday next week as a low-pressure system moves in out of Quebec.