Climate averages 1991–2020
Calgary weather
in September.
A mild, moderately wet month: the 4th warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Calgary: daytime highs average 17.5°C and nights cool to about 5.6°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 44 mm of rain on roughly 8 days, which makes September a moderately wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 42 min on an average September day.
The nearest other city in this atlas is Airdrie (28 km away). In September its highs average 16.6°C, 0.8°C cooler than Calgary, with 45 mm of rain.
Among the 86 cities listed in Canada, Calgary ranks 77th of 86 for the warmest September highs and 11th of 86 for the driest September (rainfall, lowest first). The mean September high of those 86 cities is 19.8°C; Calgary is 2.3°C cooler than that mean.
From September to October, average highs fall by 7.3°C to 10.2°C, and monthly rainfall falls from 44 mm to 24 mm.
The annual picture
September in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Calgary climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -2.9°C-13.1°C | -13.1°C | 12 | 3.7 | 8.58 h |
| February | 0.0°C-11.4°C | -11.4°C | 12 | 3.7 | 10.010 h |
| March | 4.2°C-7.6°C | -7.6°C | 21 | 5.5 | 11.812 h |
| April | 10.1°C-2.2°C | -2.2°C | 38 | 8.0 | 13.814 h |
| May | 15.7°C3.0°C | 3.0°C | 72 | 11.3 | 15.516 h |
| June | 19.1°C7.8°C | 7.8°C | 104 | 13.7 | 16.516 h |
| July | 22.7°C10.8°C | 10.8°C | 61 | 10.8 | 16.116 h |
| August | 22.3°C10.1°C | 10.1°C | 63 | 9.5 | 14.615 h |
| September, selected | 17.5°C5.6°C | 5.6°C | 44 | 7.9 | 12.713 h |
| October | 10.2°C-0.7°C | -0.7°C | 24 | 6.2 | 10.811 h |
| November | 2.1°C-7.1°C | -7.1°C | 19 | 4.9 | 9.09 h |
| December | -2.8°C-12.5°C | -12.5°C | 14 | 3.7 | 8.08 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Airdrie in SeptemberCanada · 28 kmHigh 16.6°C · Low 5.8°C · 45 mm rain
- Red Deer in SeptemberCanada · 137 kmHigh 16.6°C · Low 6.3°C · 41 mm rain
- Lethbridge in SeptemberCanada · 175 kmHigh 19.7°C · Low 8.3°C · 37 mm rain
- Sherwood Park in SeptemberCanada · 279 kmHigh 16.0°C · Low 6.7°C · 38 mm rain
- Edmonton in SeptemberCanada · 281 kmHigh 16.7°C · Low 7.2°C · 38 mm rain
- Kelowna in SeptemberCanada · 404 kmHigh 22.2°C · Low 12.7°C · 43 mm rain
- Spokane Valley in SeptemberUnited States · 439 kmHigh 23.2°C · Low 10.5°C · 22 mm rain
- Kamloops in SeptemberCanada · 440 kmHigh 21.4°C · Low 10.7°C · 35 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Calgary) is explained once on the Calgary year overview and on the Sources, method and limits page.