Those hoping for relief from the heat will have to wait until the weekend.
A heat-related special weather statement has been issued by Environment Canada for the majority of southwestern Ontario, including London-Middlesex, Oxford County, Elgin County, Huron-Perth, and Sarnia Lambton.
Windsor-Essex and Chatham-Kent have been under a heat warning since last Thursday.
According to the national weather agency's advisory, a hot and humid airmass has parked itself over the region bringing daytime highs near 30 C, that will feel closer to 40 C with the humidity on Wednesday, Thursday, and Friday. Overnight temperatures for the rest of the week are forecast to dip a bit to between 17 C to 20 C.
Areas near the shores of the Great Lakes will experience slightly cooler temperatures, the statement from Environment Canada notes.
A cold front will push the humid air out on Friday night. That will lead to slightly less sticky conditions on Saturday and Sunday, when temperatures are forecast to be 24 C and 26 C.