St. Louis climate
St. Louis is warmest in July, with average highs of 31 °C, and coldest in January, when nights average -3.7 °C. May is the wettest month (129 mm) and February the driest (63 mm). Figures are 1991–2020 climate normals.
Across a full year St. Louis averages 1,110 mm of rain, 136 days above 25 °C and 78 days below freezing.
United States · 142 m elevation · population 279,695 · 1991–2020 normals
Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month
- Warmest month July 31 °C
- Coldest month January -3.7 °C
- Driest month February 63 mm
- Wettest month May 129 mm
- Least cloud September 43 % cloud
- Hottest on record June 41 °C
- Coldest on record January -28 °C
What to expectSt. Louis through the year
St. Louis has a clear annual cycle: average daily highs run from 4.9 °C in January to 31 °C in July, a swing of 26 °C in mean temperature across the year.
Counted across a normal year, 136 days a year reach 25 °C, 64 of them reach 30 °C, 78 nights drop below freezing. The warmest reading in the 1991–2020 record is 41 °C, in June.
Rain is strongly seasonal. May averages 129 mm against 63 mm in February — 2.0 times as much. Planning around the dry months matters more here than planning around temperature.
Month by month
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 4.9 °C | 72 mm | 63 % |
| February | 7.9 °C | 63 mm | 64 % |
| March | 13.7 °C | 99 mm | 62 % |
| April | 19.8 °C | 117 mm | 58 % |
| May | 24.8 °C | 129 mm | 59 % |
| June | 29.4 °C | 109 mm | 53 % |
| July | 31.3 °C | 94 mm | 48 % |
| August | 30.7 °C | 81 mm | 46 % |
| September | 26.8 °C | 96 mm | 43 % |
| October | 20.3 °C | 89 mm | 48 % |
| November | 12.8 °C | 94 mm | 56 % |
| December | 6.8 °C | 67 mm | 63 % |
Temperature month by month
| Month | Avg high | Avg low | Mean | Record high | Record low | Days above 25 °C | Days above 30 °C | Days below 0 °C |
|---|---|---|---|---|---|---|---|---|
| January | 4.9 °C | -3.7 °C | -0.2 °C | 20.8 °C | -28.0 °C | 0 | 0 | 23 |
| February | 7.9 °C | -1.9 °C | 2.1 °C | 25.4 °C | -24.4 °C | 0 | 0 | 18 |
| March | 13.7 °C | 3.0 °C | 7.6 °C | 27.9 °C | -18.6 °C | 1 | 0 | 10 |
| April | 19.8 °C | 8.8 °C | 13.7 °C | 32.0 °C | -4.6 °C | 5 | 0 | 1 |
| May | 24.8 °C | 14.5 °C | 19.2 °C | 36.0 °C | 2.3 °C | 16 | 3 | 0 |
| June | 29.4 °C | 19.4 °C | 24.2 °C | 41.3 °C | 9.3 °C | 27 | 14 | 0 |
| July | 31.3 °C | 21.7 °C | 26.3 °C | 40.3 °C | 13.2 °C | 30 | 21 | 0 |
| August | 30.7 °C | 21.0 °C | 25.6 °C | 39.7 °C | 11.1 °C | 30 | 18 | 0 |
| September | 26.8 °C | 16.8 °C | 21.4 °C | 37.4 °C | 3.5 °C | 20 | 7 | 0 |
| October | 20.3 °C | 10.7 °C | 14.9 °C | 33.3 °C | -1.3 °C | 7 | 1 | 0 |
| November | 12.8 °C | 4.2 °C | 7.8 °C | 26.8 °C | -14.2 °C | 0 | 0 | 7 |
| December | 6.8 °C | -1.1 °C | 2.2 °C | 22.7 °C | -22.3 °C | 0 | 0 | 18 |
Rain, sun and wind month by month
| Month | Rainfall | Wet days | Daylight | Cloud cover | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 72 mm | 8 | 9.8 h/day | 63 % | 68 % | 18 km/h |
| February | 63 mm | 7 | 11 h/day | 64 % | 66 % | 19 km/h |
| March | 99 mm | 11 | 12 h/day | 62 % | 66 % | 19 km/h |
| April | 117 mm | 11 | 13 h/day | 58 % | 65 % | 20 km/h |
| May | 129 mm | 13 | 14 h/day | 59 % | 69 % | 18 km/h |
| June | 109 mm | 11 | 15 h/day | 53 % | 69 % | 15 km/h |
| July | 94 mm | 10 | 15 h/day | 48 % | 68 % | 13 km/h |
| August | 81 mm | 9 | 14 h/day | 46 % | 68 % | 13 km/h |
| September | 96 mm | 7 | 12 h/day | 43 % | 67 % | 14 km/h |
| October | 89 mm | 8 | 11 h/day | 48 % | 66 % | 17 km/h |
| November | 94 mm | 9 | 10 h/day | 56 % | 68 % | 18 km/h |
| December | 67 mm | 8 | 9.5 h/day | 63 % | 71 % | 18 km/h |
Planning a trip? See the best time to visit St. Louis.
QuestionsCommon questions about St. Louis’s climate
When is the best time to visit St. Louis?
That depends on what you want, so the honest answer is a comparison rather than a single month. May, June, September sit closest to 20 °C on average, July is the warmest month and February the driest. The month-by-month table above has the full picture.
How hot does St. Louis get?
In July, the warmest month, daily highs average 31 °C. About 64 days a year pass 30 °C. The highest value in the 1991–2020 record is 41 °C.
How cold does it get in winter?
Nights average -3.7 °C in January, the coldest month. A normal year has 78 nights below freezing.
Which month is wettest in St. Louis?
May, averaging 129 mm over 13 days with rain. The driest month is February with 63 mm. The year as a whole averages 1,110 mm.
Are these figures a forecast?
No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in St. Louis rather than what any particular week will bring. Individual years can differ substantially from the normal.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.