WEATHER · CLIMATE NORMALS · 1991–2020
Glasgow Climate — Averages by Month
What the weather in Glasgow, GBaverages 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 | 4.5 °C · coldest | 123.6 mm · wettest |
| February | 4.6 °C | 104.9 mm |
| March | 5.8 °C | 94.9 mm |
| April | 7.9 °C | 81.2 mm |
| May | 10.7 °C | 85.5 mm |
| June | 13.2 °C | 93.6 mm |
| July | 14.8 °C · warmest | 101.1 mm |
| August | 14.5 °C | 109.9 mm |
| September | 12.6 °C | 90.5 mm |
| October | 9.6 °C | 117.7 mm |
| November | 6.6 °C | 112.9 mm |
| December | 4.5 °C | 121.8 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 Glasgow — centred at 55.75°N, 4.25°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.