Weather in St. Louis

Planning your day in St. Louis? Check out current weather updates, forecasts, and useful charts right here.

St. Louis, located in the USA, is characterized by a temperate continental climate with four distinct seasons. This means that travellers can expect significant temperature fluctuations throughout the year. Winters here are cool, sometimes cold, while summers are generally warm and occasionally hot, with plenty of sunny days.

Spring and autumn in St. Louis are transitional seasons with milder temperatures, making them popular times to visit. In spring, nature comes alive, while autumn delights with pleasant coolness and colourful landscapes. Summer, especially July and August, can be quite hot, with average maximum temperatures reaching around 30-31°C. Winter months, particularly January, bring a chill, with average temperatures around freezing and the possibility of frost.

Regarding precipitation, it is distributed relatively evenly throughout the year, without a distinct rainy season. The number of rainy days per month ranges from 7 to 14, and monthly rainfall is low, averaging 2-4 mm. This suggests that while rain is possible at any time of year, it is usually not prolonged.

The annual temperature trend in St. Louis shows significant seasonal fluctuations, typical of a continental climate. The hottest month is traditionally July, when the average air temperature is 26.7°C, and daily highs regularly reach 31.4°C. In contrast, the coldest month is considered to be January: the average temperature at this time hovers around 0.8°C, with night frosts being not uncommon, and the thermometer can drop to an average of -3.1°C.

The summer period in St. Louis, spanning June, July, and August, is distinguished by warm and occasionally hot weather. Average temperatures during these months vary from 25.1°C in June to 26.7°C in July, and the daytime heat can be palpable, with maximum values often exceeding 30°C (e.g., 30.3°C in June, 31.4°C in July). Winters, from December to February, are generally cool, with average temperatures from 0.8°C (January) to 4.5°C (December), and night temperatures often dropping below freezing (e.g., -1.9°C in February). It is worth noting that diurnal temperature variations are noticeable throughout the year: the difference between average daily highs and average nightly lows is usually about 8-10°C (e.g., in March from 3.8°C to 14.0°C, in October from 10.8°C to 20.7°C), which provides some nocturnal relief even during hot summer months and highlights the variability of weather in the winter period.

Precipitation in St. Louis falls throughout the year; however, its intensity and frequency have their own seasonal characteristics, despite the generally small amount (2-4 mm per month). In winter, especially in January (average temperature 0.8°C, minimum -3.1°C), February (average temperature 3.2°C, minimum -1.9°C), and December (average temperature 4.5°C, minimum 0.3°C), precipitation often takes the form of snow or wet snow, especially considering night temperatures dropping below zero. During these winter months, there are usually about 9 days with precipitation, with the total amount being 2-3 mm.

The highest frequency of precipitation is observed in spring and the first half of summer. May is the month with the highest number of days with precipitation – on average 14 days, with a total volume of 4 mm. Precipitation also falls quite frequently in March (13 days, 4 mm), July (12 days, 4 mm), as well as in April and August (11 days and 4 mm each). This suggests that during these periods, rains are likely light or moderate, but occur more often than in other months.

The period with the least amount of precipitation and the lowest frequency can be considered the beginning of autumn. In September, only 2 mm of precipitation falls on average, and there are about 7 "wet" days. November and December are also characterized by minimal precipitation volume (2 mm each), although there are slightly more days with it (9 days each). In general, short or drizzling rains are typical for St. Louis, rather than heavy downpours, even in months with the maximum number of rainy days, which is due to the small total monthly rainfall.

When packing your suitcase for a trip to St. Louis, it is important to consider the distinct change of seasons and possible temperature fluctuations. Regardless of the time of year, comfortable walking shoes will be your best companion, as the city is conducive to walking. The principle of layering clothing is the key to comfort, as the weather can change during the day, especially in transitional seasons. A light jacket or sweater that can be taken off or put on will come in handy almost always.

If your trip falls during the summer months (June-August), when the average temperature stays around 25-27°C and the maximum can exceed 30°C, pack light, breathable clothing made from natural fabrics, sunscreen, a hat, and sunglasses. In winter (December-February), it can be cold in St. Louis, with average temperatures fluctuating around 0-4°C, and night temperatures dropping below freezing. You will need a warm jacket or coat, a hat, gloves, a scarf, and possibly thermal underwear. Given that winter precipitation may fall as snow, waterproof shoes will be useful.

Spring (March-May) and autumn (September-November) are times of changeable weather. Temperatures in spring gradually rise from cool to warm, while in autumn, conversely, they decrease. During these periods, it is worth taking clothes that are easy to mix and match: t-shirts, long-sleeve tops, sweaters, as well as a mid-season jacket. Although the monthly rainfall in St. Louis is small (2-4 mm), rainy days occur regularly (from 7 to 14 days per month). Therefore, a compact umbrella or a light waterproof jacket will be very useful in your luggage at any time of year.