The Heat Warning is expected to be with us all weekend.
Gerald Cheng from Environment Canada says most locations in northwestern Ontario can expect temperatures into the 30's.
"The whole weekend is going to be a hot weekend," predicts Cheng.
"Monday is when we start to see a change. Temperatures are dropping and we do see overnight lows getting back to the lower teens and that helps with people that are suffering from the heat."
Cheng adds that the Heat Warning can have severe consequences, depending on where you live.
"You know if you live in a house, the basement is your friend if you need to cool off, but certainly if you live in an apartment it can be excruciatingly hot, especially during this time, because indoor temperatures will not drop much because overnight temperatures are staying quite high, around 18 or 19 degrees."
The normal high for this time of year is about 20 degrees and the normal low is 10 degrees.