What should be our hottest stretch of weather so far this year should arrive in southern Ontario in time for Canada Day.

Environment Canada says hot and humid air will arrive in southern Ontario late Wednesday, ushered in by periods of scattered showers and potential thunderstorms.

As of Wednesday morning, forecasts for Waterloo-Wellington were calling for a high of 28 on Thursday, with humidex values topping out at 33, partly cloudy conditions and a very high UV risk.

Similar temperatures were expected in Oxford-Brant, Norfolk-Haldimand, Huron-Perth and Grey-Bruce, although there was a 30 per cent chance of daytime rain for areas closer to Lake Huron.

Temperatures were expected to then climb even higher, with forecast highs of 30 C for Friday, 35 C for Saturday, 33 C for Sunday and 30 C for Monday in Waterloo-Wellington, and similar values elsewhere in our coverage area, with humidex values expected to run into the 40s.

Early signs pointed to a potential chance of showers across southern Ontario during portions of Sunday and Monday, and high heat remaining in the area into the middle of the first week of July.