A heat warning has been issued for large parts of Alberta, where Environment Canada is warning daytime highs up to 36 C could linger for the next eight to 10 days.
The warning covers all of northern Alberta and most of southern Alberta, including Calgary, and extends into parts of British Columbia and northwestern Saskatchewan.
The weather office says the warning is likely to be expanded going forward.
Environment Canada says temperatures are expected to hit between 28 C and 36 C, with overnight lows between 12 C and 20 C.
The stretch of sweltering temperatures comes less than a week after the peak of another heat wave over Alberta.
Parts of northern Alberta are also under an air quality advisory because of wildfire smoke.