Environment Canada’s heat warning now spans four provinces as it expands past Ontario and reaches much of the central and eastern parts of the country.

The weather agency’s new warning applies to broad swaths of southern Ontario, southern Quebec, New Brunswick and Nova Scotia.

Environment Canada says maximum temperatures today are expected to reach or surpass 30 C and hit the low forties when combined with humidity.

It says tonight temperatures are expected to be in the low to mid-twenties, bringing little relief from the daytime heat.

The Air Quality Health Index shows southern Ontario is currently in the low to moderate risk category, with southern Quebec, New Brunswick and Nova Scotia in the low risk category.

Cooler temperatures are forecast for later Monday, although parts of Nova Scotia could continue to feel the overwhelming heat throughout the day and in to Tuesday.