St. Louis climate
St. Louis (Missouri, United States) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 13 °C56 °F, and about 1,105 mm44 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
St. Louis climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | 439 | −622 | −130 | 632.5 | 27 |
| Feb | 643 | −524 | 133 | 642.5 | 24 |
| Mar | 1355 | 134 | 745 | 933.7 | 14 |
| Apr | 2067 | 745 | 1356 | 1214.8 | 3 |
| May | 2476 | 1356 | 1966 | 1295.1 | 0 |
| Jun | 2984 | 1865 | 2475 | 1074.2 | 0 |
| Jul | 3188 | 2069 | 2678 | 1014.0 | 0 |
| Aug | 3188 | 1967 | 2577 | 933.7 | 0 |
| Sep | 2781 | 1559 | 2170 | 813.2 | 0 |
| Oct | 2068 | 846 | 1457 | 943.7 | 1 |
| Nov | 1355 | 134 | 745 | 853.4 | 12 |
| Dec | 643 | −326 | 135 | 742.9 | 23 |
| Year | 3188 | −622 | 1356 | 1,10544 | 104 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 82% | 62% | 2.1 | 9:45 |
| Feb | 80% | 65% | 2.8 | 10:42 |
| Mar | 78% | 63% | 3.8 | 11:51 |
| Apr | 76% | 57% | 5.0 | 13:10 |
| May | 78% | 60% | 5.6 | 14:16 |
| Jun | 77% | 50% | 6.4 | 14:51 |
| Jul | 74% | 47% | 6.3 | 14:37 |
| Aug | 71% | 47% | 5.6 | 13:39 |
| Sep | 70% | 43% | 4.8 | 12:23 |
| Oct | 71% | 50% | 3.4 | 11:07 |
| Nov | 76% | 54% | 2.4 | 10:01 |
| Dec | 82% | 64% | 1.8 | 9:29 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of St. Louis is like
The warmest month is July, with an average high of 31 °C88 °F and a low of 20 °C69 °F. The coldest is January, when highs average 4 °C39 °F and lows −6 °C22 °F. Seasons are strongly marked: the warmest month is on average 26.8 °C48.2 °F warmer than the coldest.
It is wet, with about 1,105 mm44 in of precipitation per year. The wettest three-month stretch is April–June, which brings 32% of the annual total. The wettest month is May (129 mm5.1 in), the driest is January (63 mm2.5 in).
Relative humidity ranges from 70% in September to 82% in December. The clearest skies (lowest average cloud amount, 43%) are typical of September. Average wind speed near the ground ranges from 6 km/h (3 mph) in August to 10 km/h (6 mph) in February. Daylight lasts from about 9.5 hours in December to 14.8 hours in June.
A lasting snow cover is typical in January and February. In those months the average snow depth in the reanalysis exceeds 10 cm. It is deepest in January, at about 13 cm.
Best time to visit St. Louis
Based on these averages, the most comfortable months for sightseeing and outdoor activities are September. Average highs then reach 27 °C81 °F to 27 °C81 °F. Precipitation is 81 mm3.2 in to 81 mm3.2 in per month.
The most challenging month is January, which is cold, with average highs of 4 °C39 °F.
Comfort score: months are ranked by how close they come to an ideal. That means an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for St. Louis
- Winter (December–February) — highs 439 to 6 °C43 °F, lows −622 to −3 °C26 °F, about 67 mm2.6 in of precipitation a month. Pack a warm coat, layers and closed shoes and shoes with good grip, as frost is common.
- Spring (March–May) — highs 1355 to 24 °C76 °F, lows 134 to 13 °C56 °F, about 114 mm4.5 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Summer (June–August) — highs 2984 to 31 °C88 °F, lows 1865 to 20 °C69 °F, about 100 mm3.9 in of precipitation a month. Pack very light, breathable clothing, a sun hat and plenty of water and an umbrella or light rain jacket.
- Autumn (September–November) — highs 1355 to 27 °C81 °F, lows 134 to 15 °C59 °F, about 87 mm3.4 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket and an extra layer for the cooler mornings and evenings.
How St. Louis compares
The nearest larger place is Indianapolis, about 370 km to the east. Compared with it, St. Louis is on average 1.9 °C3.4 °F warmer. It receives a similar amount of precipitation. The difference is largest in March (2.4 °C4.3 °F warmer).
World Climates covers 222 places in the United States. By annual mean temperature, St. Louis is the 132nd warmest of them. By annual precipitation, it is the 92nd wettest. See all of them on the United States climate page.
Some places in other countries have a very similar pattern of temperature and rainfall. The closest matches are Craiova (Romania, Dfa), Kragujevac (Serbia, Cfa) and Maykop (Russia, Cfa).
Nearby places
- Climate in Springfield 139 km · 12 °C53 °F · 1,001 mm39 in
- Climate in Columbia 189 km · 13 °C55 °F · 1,044 mm41 in
- Climate in Peoria 236 km · 11 °C52 °F · 983 mm39 in
- Climate in Evansville 242 km · 14 °C56 °F · 1,243 mm49 in
- Climate in Springfield 314 km · 13 °C56 °F · 1,213 mm48 in
- Climate in Davenport 324 km · 10 °C51 °F · 924 mm36 in
- Climate in Clarksville 342 km · 15 °C58 °F · 1,316 mm52 in
- Climate in Joliet 369 km · 10 °C51 °F · 985 mm39 in
Frequently asked questions
What is the warmest month in St. Louis?
July is the warmest month in St. Louis. Its average high is 31 °C (88 °F) and its average low is 20 °C (69 °F).
What is the coldest month in St. Louis?
January is the coldest month. Its average high is 4 °C (39 °F) and its average low is -6 °C (22 °F).
When does it rain the most in St. Louis?
May is the wettest month with about 129 mm (5.1 in) of precipitation. January is the driest with about 63 mm (2.5 in).
What is the best time to visit St. Louis?
Judging by long-term averages, the most comfortable months are September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station. So they can differ from airport records. The gaps are largest on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.