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, when the average snow depth in the reanalysis exceeds 10 cm (deepest in January, 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 of 27 °C81 °F to 27 °C81 °F with 81 mm3.2 in to 81 mm3.2 in of precipitation 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 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
Compared with Indianapolis, about 370 km to the east, St. Louis is on average 1.9 °C3.4 °F warmer and receives a similar amount of precipitation. The difference is largest in March (2.4 °C4.3 °F warmer).
Of the 222 places in the United States covered by World Climates, St. Louis is the 132nd warmest by annual mean temperature and the 92nd wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern: Craiova (Romania, Dfa), Kragujevac (Serbia, Cfa) and Maykop (Russia, Cfa).
Nearby places
- Springfield 139 km · 12 °C53 °F · 1,001 mm39 in
- Columbia 189 km · 13 °C55 °F · 1,044 mm41 in
- Peoria 236 km · 11 °C52 °F · 983 mm39 in
- Evansville 242 km · 14 °C56 °F · 1,243 mm49 in
- Springfield 314 km · 13 °C56 °F · 1,213 mm48 in
- Davenport 324 km · 10 °C51 °F · 924 mm36 in
- Clarksville 342 km · 15 °C58 °F · 1,316 mm52 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, with an average high of 31 °C (88 °F) and an average low of 20 °C (69 °F).
What is the coldest month in St. Louis?
January is the coldest month, with an average high of 4 °C (39 °F) and an average low of -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 — most of all 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.