WEATHER · CLIMATE NORMALS · 1991–2020
Columbia Climate — Averages by Month
What the weather in Columbia, 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 | 7.7 °C · coldest | 91.5 mm |
| February | 9.5 °C | 88.3 mm |
| March | 13.3 °C | 92.1 mm |
| April | 18.0 °C | 87.4 mm |
| May | 22.2 °C | 79.3 mm |
| June | 25.7 °C | 111.8 mm |
| July | 27.3 °C · warmest | 116.8 mm · wettest |
| August | 26.5 °C | 113.6 mm |
| September | 23.6 °C | 97.8 mm |
| October | 18.0 °C | 86.4 mm |
| November | 12.5 °C | 73.6 mm |
| December | 9.0 °C | 95.2 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 Columbia — centred at 34.00°N, 81.00°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.