St. Louis, located at the confluence of the Mississippi and Missouri Rivers, features a humid continental to humid subtropical climate with four distinct seasons. Summers are hot and humid, winters are cold and brisk, and spring and autumn offer dramatic weather swings. The city’s varied climate supports vibrant festivals, lush parks, and a dynamic urban culture year-round.
The best times to travel section shows how the months compare for a visit, so you can find the time of year that fits what you want to do.
Background colours of the months:
The colour shows the typical temperature: yellow (hot), green (mild) and blue (cold). How strong the colour is shows the travel season: full colour means high season, soft colour means shoulder season and soft-striped means off season.
Weather symbols:
Each month has one symbol showing what the weather is typically like, such as hot and sunny, freezing or a rainy or snowy season. Use them to quickly spot months that match the weather you want, or to avoid the ones that don't.
Crowdedness:
The people icon shows how busy the place usually is. The more people, the more crowded it gets.
Additional notes:
The grey info boxes point out special things worth knowing, like recurring weather issues or seasonal events.
St. Louis experiences a true four-season climate shaped by its central U.S. location and exposure to both Arctic and Gulf air masses. Summers (June–August) are hot and humid, with average highs of 30–32°C and frequent days above 32°C. Humidity is high, and thunderstorms are common, with July and August each bringing nearly 100 mm of rain. Heatwaves can push temperatures above 37°C, though nights are usually warm and muggy. Sunshine is abundant, with up to 10 hours per day in summer, but brief, intense storms can bring hail, damaging winds, and, occasionally, tornadoes.
Winters (December–February) are cold and brisk, with average highs of 3–7°C and lows dipping to –6°C. Snowfall averages 40–45 cm per season, with the snowiest months being January and February. Extended periods of extreme cold are rare, but cold snaps can drop temperatures below –10°C. Winters are the driest season, with about 150 mm of precipitation across three months, and days are short and partly cloudy. Spring (March–May) and autumn (September–November) are transitional, featuring rapidly changing weather, frequent rain, and dramatic temperature swings. Spring is the wettest season, with nearly 270 mm of rain, and is also the most tornado-prone. Autumn offers mild, sunny days, vibrant foliage, and comfortable nights. Winds are generally moderate (15–20 km/h), but can be brisk during storms. Annual precipitation averages 870–1,100 mm, spread fairly evenly throughout the year, and St. Louis enjoys about 2,600 hours of sunshine annually.
| Average climate data for St. Louis, United States | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 4 | 7 | 13 | 20 | 25 | 29 | 32 | 31 | 27 | 20 | 13 | 6 | 32 |
| Average minimum temperature (°C) | -5 | -2 | 3 | 9 | 14 | 19 | 22 | 21 | 16 | 9 | 3 | -3 | -5 |
| Average precipitation (mm) | 61 | 56 | 84 | 94 | 119 | 109 | 103 | 76 | 78 | 85 | 100 | 72 | 1,038 |
| Average rainfall days (days) | 9 | 8 | 10 | 11 | 12 | 10 | 9 | 8 | 7 | 9 | 10 | 9 | 113 |
| Average snowfall (mm) | 142 | 108 | 59 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 18 | 112 | 448 |
| Average snowfall days (days) | 5 | 3 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 | 15 |
| Average relative humidity (%) | 73 | 71 | 69 | 64 | 66 | 68 | 68 | 71 | 72 | 68 | 72 | 75 | 70 |
| Average daily daylight hours (h) | 9 | 10 | 12 | 13 | 14 | 14 | 14 | 13 | 12 | 11 | 10 | 9 | 12 |
| Average daily sunshine hours (h) | 5 | 5 | 6 | 7 | 8 | 9 | 10 | 8 | 7 | 6 | 4 | 4 | 7 |
| Average UV index | 2 | 3 | 5 | 7 | 8 | 9 | 9 | 9 | 7 | 4 | 3 | 2 | 6 |
The best time to visit St. Louis is in spring (April–May) and fall (September–October), when temperatures are mild, humidity is lower, and the city’s parks and neighbourhoods are at their most beautiful. These months offer ideal conditions for festivals, outdoor adventures, and exploring cultural attractions without the extremes of summer heat or winter cold.
The least favourable time to visit is during the peak of summer (July–August), when heat, humidity, and frequent thunderstorms can make outdoor activities uncomfortable. Winter (December–February) is also challenging for some, with cold, brisk weather and occasional snow or ice limiting outdoor plans.
St. Louis has a humid continental to humid subtropical climate with hot, humid summers, cold winters, and dramatic weather swings in spring and autumn. Rain falls year-round, and the city experiences all four seasons distinctly.
April–May and September–October are the best times to visit, with mild temperatures, lower humidity, and vibrant parks. These months are ideal for festivals, sightseeing, and outdoor activities.
Yes, St. Louis averages 40–45 cm (16–18 inches) of snow per winter, mostly from December to February. Snow events are usually light to moderate, but occasional storms can bring heavier accumulations.
Summer highs average 30–32°C, with July and August being the hottest months. Heatwaves can push temperatures above 37°C, and humidity is high, making the heat feel more intense.
St. Louis receives about 870–1,100 mm of precipitation annually, with the wettest months in spring. Thunderstorms are common in summer, and rain falls fairly evenly throughout the year.
In spring and autumn, pack layers and a rain jacket. For summer, bring light, breathable clothing, sun protection, and an umbrella. In winter, wear warm layers, a waterproof coat, and sturdy shoes for snow or ice.
Yes, St. Louis is prone to severe thunderstorms and tornadoes, especially in spring. It’s wise to check weather alerts during these seasons and be prepared for sudden changes.
The warmest month, with the highest average maximum temperature, is July (31.8 °C). The month with the lowest average maximum temperature is January (4.5 °C). Overall, the average maximum temperature over the whole year is 18.9 °C.
The month with the highest average minimum temperature is July (21.7 °C). The coldest month, with the lowest average minimum temperature, is January (-4.7 °C). Overall, the average minimum temperature over the whole year is 8.8 °C.
The wettest month, with the highest amount of precipitation, is May (119.4 mm). The driest month, with the least amount of precipitation, is February (56.1 mm). Over the whole year there are 1,037.7 mm of rainfall on average.
The month with the most days of rain is May (12 days). The month with the fewest days of rain is September (7.3 days). Over the whole year there are 113 days of rain on average.
The month with the most snowfall is January (142.4 mm). The months with the least snowfall are May, June, July, August, September and October (0 mm). Over the whole year there are 448.4 mm of snowfall on average.
The month with the most days of snowfall is January (4.8 days). The month with the fewest days of snowfall is September (0 days). Over the whole year there are 14.9 days of snowfall on average.
The month with the highest average relative humidity is December (75.3 %). The month with the lowest average relative humidity is April (63.6 %). The overall average relative humidity over the whole year is 69.9 %.
The month with the longest days, so the most daylight, is June (Average daylight: 14.1 h). The month with the shortest days, so the least daylight, is December (Average daylight: 9 h). Over the whole year there are 11.8 h of daylight per day on average.
The month with the most sunshine per day is July (Average sunshine: 10 h). The month with the least sunshine per day is November (Average sunshine: 4 h). Over the whole year there are 6.6 h of sunlight per day on average.
The months with the highest average UV index are June, July and August (UV index: 9). The months with the lowest average UV index are January and December (UV index: 2). Over the whole year the average UV index is 5.7.
