WEATHER · CLIMATE NORMALS · 1991–2020
St Petersburg Climate — Averages by Month
What the weather in St Petersburg, RUaverages 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 | -5.5 °C | 52.6 mm |
| February | -5.8 °C · coldest | 41.6 mm |
| March | -2.1 °C | 42.6 mm |
| April | 4.1 °C | 44.3 mm |
| May | 10.1 °C | 53.8 mm |
| June | 14.1 °C | 69.2 mm |
| July | 17.2 °C · warmest | 70.9 mm |
| August | 15.8 °C | 76.3 mm · wettest |
| September | 11.2 °C | 62.3 mm |
| October | 5.3 °C | 70.7 mm |
| November | 0.4 °C | 66.3 mm |
| December | -2.9 °C | 59.6 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 St Petersburg — centred at 60.00°N, 30.25°E. 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.