Environment Canada has issued a frost advisory for the City of Toronto as a colder-than-normal weather system moves into Southern Ontario, bringing with it "frost or freeze conditions" and potentially "several centimetres of snow" between Sunday night and Monday morning.

No, you aren't reading a story from November — today is indeed May 10, and you are indeed going to need a warm winter coat if you plan on going outside this week.

"Near freezing temperatures overnight are expected to persist for much of the week as a cold air mass has settled into the area," reads the federal weather agency's advisory, published just before 11 a.m. on Sunday morning. "Take preventative measures to protect frost-sensitive plants and trees."

Meteorologists say that we can expect "near zero" temperatures overnight after temperatures drop from a daytime high of 10 C, consistent with the up-down-up-down weather pattern Toronto has been experiencing in recent days.

By Monday night, we're looking at a forecasted low of just -4 C.

Wild weather conditions are expected through much of the week, but should taper off in time for the long weekend. Image via Environment Canada.

On Tuesday, EnviroCan predicts a daytime high of 12 C followed by a steep drop to -2 C overnight. This volatile system should stick around for most of the week, no doubt wreaking havoc on any newly-planted tulips which aren't sufficiently protected.

Fortunately, this unsettled and unseasonable weather pattern should be over in time for the long weekend.

The Weather Network reports that, after one more blast of Arctic air earlier in the week, temperatures will grow closer to seasonal (albeit with some rain in the mix).

"As we head into the long weekend, a very warm pattern is expected over the eastern U.S. but we don't think that warmth will quite make it to southern Ontario," says Weather Network meteorologist Dr. Doug Gillham.

"Our temperatures will still be on the cool side of seasonal but they will also be 5 to 10 degrees warmer than what we are seeing this weekend."