The agency says a warm-up between 3 and 5 C on Wednesday afternoon followed by another abrupt drop in temperature late afternoon and early evening will make surfaces slippery across Hamilton and the Niagara region.
“A cold front will push through the region which will cause temperatures to abruptly drop below freezing in time for the evening commute,” the statement said.
“Surfaces such as highways, roads, walkways and parking lots may become icy and slippery.”
The temperature fluctuations are coming just days after much of southern Ontario endured snowstorms which dropped between 35 and 50 cm of the white stuff.
Wednesday’s high of 5 C is expected to drop to -13 C overnight into Thursday morning. The wind chill is expected to make it feel like -20 C.
Global News chief meteorologist Anthony Farnell says the change is due to a system moving in from the Prairies.
“There’s a lot of snow … and it’s going to refreeze late this afternoon,” Farnell said.
“It’s the cold that’s coming in from the Prairies that’s already been making headlines with extreme cold weather alerts.”
Hamilton is expected to face that system on Thursday with temperatures steady all day near -11 C.