Carstairs residents can look forward to an unseasonably warm and sunny start to the week, with temperatures climbing well above the seasonal normal. Environment Canada is forecasting a high of 27°C for Monday, September 21, 2026, which is about 12 degrees warmer than the typical late-September high of 15°C.
The sunny conditions are expected to stick around through Wednesday, with daytime highs near 19 to 20°C. That means ideal weather for getting outside, whether you’re working in the yard, going for a walk, or just enjoying the late-summer feel in central Alberta.
But the warm days come with a catch. Overnight lows are expected to drop to around 3°C Monday night, bringing a risk of frost. Gardeners and anyone with sensitive plants should take precautions, especially with temperatures forecast to dip to 0°C by Saturday night.
The warm spell is not expected to last all week. By Friday, September 25, periods of rain are expected with temperatures dropping to around 8°C, and Saturday night carries a 60 percent chance of showers. That’s a sharp change from the early-week warmth, so locals may want to make the most of the sunny days while they can.
The mild weather fits a broader pattern for September 2026, with above-seasonal temperatures forecast across most of Canada. An intensifying El Niño is influencing fall weather, and The Weather Network’s fall outlook predicts above-normal temperatures and below-normal precipitation for Alberta, delaying consistent winter weather.
