WEATHER · CLIMATE NORMALS · 1991–2020
Phoenix Climate — Averages by Month
What the weather in Phoenix, USaverages 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 | 12.1 °C | 33.3 mm |
| February | 14.0 °C | 38.5 mm · wettest |
| March | 17.8 °C | 27.5 mm |
| April | 22.2 °C | 8.4 mm |
| May | 27.5 °C | 4.4 mm |
| June | 32.9 °C | 2.0 mm |
| July | 34.9 °C · warmest | 20.3 mm |
| August | 34.1 °C | 31.3 mm |
| September | 30.9 °C | 25.8 mm |
| October | 24.1 °C | 20.7 mm |
| November | 16.9 °C | 17.7 mm |
| December | 11.5 °C · coldest | 29.6 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 Phoenix — centred at 33.50°N, 112.00°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.