St. Louis, MO Weather
St. Louis hourly forecast: next 24 hours
Today's high of 97°F (36°C) is about 15°F (8°C) above the typical September high of 82°F (28°C).
Current conditions in detail
St. Louis weather tomorrow (Friday, September 18)
Tomorrow in St. Louis looks sunny, with a high of 99° and an overnight low of 79°. Precipitation chance is modest at 17%. Winds top out near 9 mph, and the UV index reaches 7 (high).
St. Louis 14-day forecast
About the weather in St. Louis
St. Louis runs one of the wider annual swings in our dataset: 26°C separates the average July from the average January. Afternoons reach 88°F (31°C) at the peak of summer and 41°F (5°C) at the depth of winter, with 126 days of measurable precipitation through the year.
St. Louis weather: quick facts
- Hottest month: July - highs near 88°F (31°C)
- Coldest month: January - highs near 41°F (5°C)
- Decade extremes (2015-2024): 104°F (40°C) high · -7°F (-22°C) low
- Wettest month: July (13 rainy days) · Sunniest: July (11.8 h sun/day)
- Climate type: humid subtropical
- Annual swing: 26°C between the average warmest and coolest month · day to night: 10°C
- Snow: about 8 days a year
- Months averaging 30°C or hotter: 2
- Average humidity: 69%
Temperatures through the year
The wettest month is July (6.9 inches (174 mm) across 13 days) and the driest February. At its warmest, in July, St. Louis runs to 88°F (31°C) in the afternoon and back to 71°F (22°C) by dawn. January is the coolest month, with highs of 41°F (5°C) and lows near 25°F (-4°C). Snow falls on roughly 8 days a year, mostly November through March.
Rain, sun and snow
Overnight lows average at or below freezing for 3 months, December through February. Between the average July and the average January lie 26°C, a wider spread than roughly 86% of the cities we track. July is the brightest month at 11.8 hours of sun a day, against an annual average of 8.8. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 104°F (40°C) and the lowest daily minimum -7°F (-22°C).
Season by season
Spring (March through May)
Spring in St. Louis is mild, with daytime highs averaging 66°F (19°C) and nights around 47°F (8°C); rain falls on around 39 of the 90 days.
Summer (June through August)
Summer is hot here - highs near 86°F (30°C), nights near 69°F (20°C), and rain falls on around 37 of the 90 days. Daylight is generous - around 11.5 hours of sun a day. With the moisture factored in, afternoons feel hotter than the reading suggests - the humidity and dew point converter shows why.
Fall (September through November)
Through fall, St. Louis brings comfortable warmth: 69°F (20°C) by day, 51°F (10°C) after dark, and expect showers on roughly 26 days across the season.
Winter (December through February)
Winter in St. Louis stays firmly cold, with daytime highs averaging 45°F (7°C) and nights around 28°F (-2°C); expect showers on roughly 25 days across the season, plus about 6 snowy days.
Average temperatures in St. Louis by month
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 41° | 25° | 9 | 3.2 in | 5.7 h/day | 69% |
| February | 46° | 27° | 8 | 2.7 in | 7.1 h/day | 66% |
| March | 57° | 38° | 13 | 5.5 in | 7.5 h/day | 67% |
| April | 66° | 46° | 11 | 5.0 in | 9.0 h/day | 65% |
| May | 76° | 58° | 14 | 5.4 in | 10.2 h/day | 71% |
| June | 86° | 67° | 11 | 4.5 in | 11.6 h/day | 68% |
| July | 88° | 71° | 13 | 6.9 in | 11.8 h/day | 73% |
| August | 85° | 69° | 13 | 5.4 in | 11.0 h/day | 74% |
| September | 82° | 63° | 8 | 4.7 in | 10.2 h/day | 69% |
| October | 69° | 51° | 9 | 3.6 in | 8.1 h/day | 67% |
| November | 55° | 38° | 9 | 3.3 in | 7.0 h/day | 69% |
| December | 47° | 31° | 8 | 3.2 in | 6.0 h/day | 71% |