Heat warnings expanded as daytime highs forecast to sit around 30 C for most of this week

Heat warnings (pink) issued by Environment and Climate Change Canada on Aug. 26, 2025.

Calgary has been added to the expanded heat warning from Environment and Climate Change Canada (ECCC) as most of the west navigates a prolonged heat event.

Daytime highs in Calgary will be at least eight degrees above seasonal with lows around 14 C.

Most of Alberta will reach highs of at least 30 C by Wednesday, but the heat warnings are not as widespread as the warmth due to the overnight temperatures.

For all of Alberta (outside of the southernmost regions) heat warnings are issued by ECCC when daytime highs reach at least 29 C with lows of at least 14 C for at least two consecutive days.

Under mostly clear skies, many rural communities will struggle to reach double-digit lows over the next few days which is why they are not currently under a heat warning.

Urban centres – especially larger ones – tend to have higher daily low temperatures in situations like these due to non-vegetative surfaces emitting stored heat that is absorbed during the day.

In their warning on Tuesday morning the national weather agency explains, “Heat warnings are issued when very high temperature conditions are expected to pose an elevated risk of heat illnesses, such as heat stroke or heat exhaustion.”

Among their suggestions to help mitigate the additional stress health, ECCC advises taking breaks from the heat and staying hydrated.

As this heat event continues there will be increased concern around wildfire risk as all three fundamentals will be in place.

More simply - when an area with an ample fuel source (e.g. vegetation) experiences seven to 10 days of hot dry weather, there is often an increased likelihood of thunderstorm activity once that stable weather pattern changes.

After a wet spring across many communities the combination of climate, vegetation, and ignition are all likely to force the wildfire danger risk up over the coming days.

Most of the region will experience sunshine with minimal wind for the next few days, with no chance of active weather.