WEATHER · CLIMATE NORMALS · 1991–2020
Calgary Climate — Averages by Month
What the weather in Calgary, CAaverages across a standard 30-year period. Each month's figure is the 1991–2020 mean temperature and total rainfall from the ERA5 reanalysis — the long-run normal a place settles around, not a forecast for any particular day.
Month-by-month normals
| Month | Avg temperature | Avg rainfall |
|---|---|---|
| January | -7.7 °C · coldest | 16.2 mm |
| February | -6.0 °C | 16.4 mm |
| March | -1.9 °C | 25.8 mm |
| April | 4.3 °C | 42.9 mm |
| May | 9.8 °C | 77.1 mm |
| June | 13.5 °C | 109.5 mm · wettest |
| July | 16.4 °C · warmest | 65.2 mm |
| August | 15.6 °C | 66.9 mm |
| September | 10.9 °C | 46.6 mm |
| October | 4.3 °C | 28.1 mm |
| November | -2.5 °C | 23.1 mm |
| December | -7.1 °C | 17.5 mm |
How to read these numbers
These are reanalysis normals, not readings from a single weather station. They come from the ERA5 0.25° (~25 km) global reanalysis grid, sampled at the grid cell nearest Calgary — centred at 51.00°N, 114.00°W. A reanalysis blends observations with a physics model onto an even grid, so a coastal or mountain city's cell can read a little cooler, warmer, wetter or drier than the city centre itself. The month-to-month shape — when it's hot, when it rains — is what these normals capture best.
“Normal” means the 1991–2020 average, the current World Meteorological Organization standard period. A normal is what a place tends toward over decades — any single day, month or year can and will depart from it.