Risk of frost in the forecast for Waterloo region, Guelph Monday night

Cover your tomatoes because there's a risk of frost Monday night as temperatures dip to 3 C, Environment Canada says.

Temperatures to go up to 24 C by Wednesday, then back down into teens for weekend

Environment Canada says there's a risk of frost in parts of Waterloo region, Guelph and Wellington County Monday night. (Kate Bueckert/CBC)

Cover plants and bring tomatoes inside — Environment Canada says there is a risk of frost Monday in Waterloo region as temperatures dip down to 3 C overnight.

Meteorologist Gerald Chang says it's not a frost advisory because the temperatures won't hit the freezing mark.

"There could be some odd places that could get really close," he said. "When it's consistently we see a wide area of the region getting down to zero, then that's when we issue a frost advisory."

The risk of frost is also in the forecast for Guelph and Wellington County, where areas could see the temperature drop as low as 2 C.

Chang also warned of some fog patches early Tuesday morning "so if one does have to commute, if you have to be out there driving, be careful because the visibility could be locally reduced."

Expect big swings in temperatures

Temperatures will be up and down this week in the region, with a high of 24 C in the forecast on Wednesday but then back down to the mid-teens by the weekend. Chang says the region was spoiled this summer with warm temperatures so the cooler weather lately may seem like a shock to people.

"It is below seasonal, but it is the reality because we are heading closer to astronomical fall, which happens on September 22nd," he said. "Keep in mind, too, as we head closer to winter, the normal [temperature] is also falling."

Daytime highs are usually around 20 C and overnight lows of 9 C in the region at this time of year, but September can be a bit of a rollercoaster temperature wise, he said, because it's a transitional month.

"We always get these different air masses, so big swings in temperature are very typical for this time of year," he said.

"As we head into October, November more of these big swings will happen and we have to dress for them. And of course, we want to spend most of our time outside, that's the safest place to be, so we certainly want to be dressing appropriately at this time."


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