It's typically 11°C in the Toronto this time of year -- but on Thursday, daily highs were in the mid-to-low twenties.
The day started off with thick fog for a few communities in southern Ontario, but it cleared out by early this afternoon.
Many locations saw record-breaking temperatures -- like Collingwood, which reached a daily high of 24.5°C, and Markham, which peaked at 22.3°C.
While Welland didn't break a record, it did get up to 25.8°C, making it the country's hotspot.
"The strong low pressure system that brought flurries to the Prairies is now sliding through northern Ontario," says Brian Dillon, a meteorologist at The Weather Network.
"Ahead of this, morning fog, combined with southwesterly winds, led to above-seasonal temperatures."
But according to Dillon, the warm spell will be short-lived.
"The temperature will begin to fall on Friday and continue to get colder though the weekend," he says. "Between Saturday and Hallowe'en, which is on Wednesday, the daily highs should be below 10°C."
Visit the Alerts section of the website to keep on top of watches and warnings across the country.