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Contents
- The climate of St. Louis
- The best time to visit St. Louis
- The worst time to visit St. Louis
- Spring weather in St. Louis
- Summer weather in St. Louis
- Autumn weather in St. Louis
- Winter weather in St. Louis
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average humidity
- Average rainfall
- Average rainfall days
- Average snowfall
- Average snowfall days
- Average daylight
- Average sunshine
- Average UV index
A beautiful twilight over the Gateway Arch in St. Louis, Missouri
Climate and monthly weather forecast
The climate of St. Louis
Belonging to the humid subtropical climate zone, St. Louis, Missouri, encounters a variety of weather conditions over the course of the year. This milieu is primarily characterized by its lack of a dry season, with sufficient moisture persisting year-round. This city's geographic position, nestled along the Mississippi River in the central United States, adds another layer of environmental complexity, strongly influencing its observed weather patterns.
Examining the weather patterns, it becomes clear that St. Louis experiences a pronounced shift in various climatic parameters throughout the year. During January, the coldest month, temperatures often plummet to 23.7°F (-4.6°C), while during July, they can rocket up to a sweltering 89.1°F (31.7°C). Humidity levels remain relatively stable, albeit with minor fluctuations between 63.5% in April and 75.8% in December. Rainfall varies from 2.2" (56mm) in February to 4.7" (119mm) in May, accompanied by a shift in rainy days from 8 in February to 11.9 in May. Particularly interesting is the significant absence of snow from May to November, with January and December recording the highest snowfall of 5.6 and 4.4" (112mm), respectively.
The city's weather also showcases some unique patterns. Even though July and August are the warmest months, these months do not record the highest rainfall. Instead, May records the highest rainfall. On the other hand, St. Louis experiences no snowfall from May to November, a characteristic weather pattern for a subtropical climate.
Examining the weather patterns, it becomes clear that St. Louis experiences a pronounced shift in various climatic parameters throughout the year. During January, the coldest month, temperatures often plummet to 23.7°F (-4.6°C), while during July, they can rocket up to a sweltering 89.1°F (31.7°C). Humidity levels remain relatively stable, albeit with minor fluctuations between 63.5% in April and 75.8% in December. Rainfall varies from 2.2" (56mm) in February to 4.7" (119mm) in May, accompanied by a shift in rainy days from 8 in February to 11.9 in May. Particularly interesting is the significant absence of snow from May to November, with January and December recording the highest snowfall of 5.6 and 4.4" (112mm), respectively.
The city's weather also showcases some unique patterns. Even though July and August are the warmest months, these months do not record the highest rainfall. Instead, May records the highest rainfall. On the other hand, St. Louis experiences no snowfall from May to November, a characteristic weather pattern for a subtropical climate.
The best time to visit St. Louis
A visit to St. Louis is most enjoyable during spring and fall due to mild temperatures and lower humidity levels. Particularly, the months of April and May offer comfortable conditions with temperatures ranging from 47.2°F (8.4°C) to 67.4°F (19.7°C) and humidity around 63.5%. In the fall, September and October are perfect months to experience the city as temperatures rest from 49°F (9.4°C) to 68.5°F (20.3°C) with a balanced humidity around 68.7%.
The worst time to visit St. Louis
St. Louis can exhibit extreme weather conditions during the summer and winter. The summer months from June to August, with temperatures varying from 76.3°F (24.6°C) to 89.1°F (31.7°C) and high humidity levels, could make outdoor activities a challenge. In the winter, December to February, temperatures often plummet to below freezing and St Louis experiences significant snowfall, making it a difficult period for travel and outdoor adventures.
Spring weather in St. Louis
Spring in St. Louis is a time of gradual warming, with temperatures routinely ranging from 36.6°F (2.6°C) to 67.4°F (19.7°C). Rainfall rates rise during this season, peaking at 4.7" (119mm) in May. Spring is also unique in that it tends to be relatively sunny with daylight hours increasing from 12 hours in March to 14.3 hours in May, and sunshine hours rising to 8.6 hours per day by May.
Summer weather in St. Louis
Summer brings persistent heat to St. Louis. Throughout this season, temperatures consistently hover between a comfortable 57.2°F (14°C) and a searing 89.1°F (31.7°C). Humidity levels elevate during the summer months as well, peaking at 68% in July. Despite these conditions, St. Louis experiences a dip in rainfall in summer, a stark contrast to spring’s considerable precipitation.
Autumn weather in St. Louis
Autumn is a pleasant season in St. Louis as temperatures cool from the intense summer heat. Throughout the fall, daily highs slide from 80.2°F (26.8°C) in September to 42.5°F (5.8°C) by December, creating a refreshing transition into winter. The autumn months bring a relatively fair share of rainfall to the city, in amounts ranging from 3" (76mm) in September to 2.8" (71mm) in December.
Winter weather in St. Louis
Winter in St. Louis is characterized by cold temperatures and significant snowfall. With lows of 23.7°F (-4.6°C) in January and highs only reaching 42.5°F (5.8°C) in December, the city definitely experiences a cold season. Alongside, there is distinguished snowfall, particularly in January, which receives an average of 5.6" (142mm) of snow over 4.7 days during the month.
Weather in January
January in St. Louis begins the year firmly within the grips of the winter season. Freezing conditions are predominant, with the lowest mean temperature of 23.7°F (-4.6°C). Winterscape often includes snowfall totaling 5.6" (142mm) across the city. Weather in January »
Weather in February
February sees a slight easing of January’s harsh winter conditions; days start to lengthen and temperatures, albeit marginally, show an upward trend appreciably. The average temperature rises from January but the conditions remain chilly at 27.6°F (-2.4°C). Weather in February »
Weather in March
March is characteristic of transitional weather in St. Louis, Missouri. The mercury level steadily rises, hinting at the forthcoming arrival of spring. This month sees a significant jump in average temperatures to 36.6°F (2.6°C). The snowfall finally dwindles, signaling the end of the winter season. Weather in March »
Weather in April
April in St. Louis signifies the full-fledged arrival of spring. A significant improvement in weather conditions becomes evident with the mean temperature increasing substantially. The temperature ranges from 47.2°F (8.4°C), warming the day considerably. Weather in April »
Weather in May
May dawns with improved weather conditions and temperatures, making it ideal for outdoor activities and explorations. The high temperatures rise further, granting the city a pleasant, slightly warm ambiance. The city basks in the highest average temperatures of 57.2°F (14°C) experienced this year. Weather in May »
Weather in June
St. Louis experiences the official advent of summer in June. Temperatures continue their upward incline, creating warm, typically summery conditions. Average daytime temperatures climb to a pleasant 66.8°F (19.3°C), perfect for enjoying an outdoor picnic or a leisurely day boating on the Mississippi. Weather in June »
Weather in July
July is the warmest month of the year in St. Louis. High temperatures reach their zenith in this month, registering an all-year high of 71°F (21.7°C). Residents and tourists alike eagerly anticipate the quintessential southern summer, filled with sunny days and warm nights. Weather in July »
Weather in August
The weather in August carries forward the warmth and high humidity of July. Despite a slight dip in temperatures, the average remains notably high at 69.4°F (20.8°C). St. Louis continues to bask in long daylight hours, frequently punctuated by sudden bursts of summer rainstorms. Weather in August »
Weather in September
September is a transitional month, marking the beginning of fall in St. Louis, Missouri. As the month progresses, daily temperatures gradually drop, providing relief from the summer heat. The average temperature lowers to a comfortable 60.6°F (15.9°C). Weather in September »
Weather in October
October brings the full splendor of autumn to St. Louis with its vibrant foliage and crisp air. Temperatures maintain a steady drop, bestowing upon the city a temperate and clear climate throughout October. The temperature averages about 49°F (9.4°C), ideal for exploring the city's stunning autumn-accented landscapes. Weather in October »
Weather in November
November in St. Louis represents late fall, with residents preparing for the upcoming winter season. Average temperatures decline appreciably, providing a noticeable chill indicative of the approaching winter. Around this time, the city experiences a low temperature of 38.1°F (3.4°C). Weather in November »
Weather in December
December in St. Louis is firmly within the winter season. Bitter cold conditions greet residents, often accompanied by snow. Temperatures plummet to their second-lowest of the year, averaging at 26.9°F (-2.8°C). As a result, the city experiences winter's first significant snowfall since the onset of the year-end season. Weather in December »
Updated: Aug 30, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What part of the year is the coldest?
The coldest temperatures occur during January, when averages reach a peak of 39.9°F (4.4°C) and a low of 23.7°F (-4.6°C).
How many days does it rain?
In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.94" (1040mm) of precipitation.
When does it snow?
January through April, November and December are months with snowfall.
What is the snowiest month?
January is the month with the most snowfall in St. Louis. Snow falls for 4.7 days and accumulates 5.59" (142mm) of snow.
How many days does it snow in St. Louis?
Throughout the year, there are 14.5 snowfall days, and 17.72" (450mm) of snow is accumulated.
What are the months with the lowest UV index?
January and December, with an average maximum UV index of 2, are months with the lowest UV index.
What is the driest month?
February is the month with the least rainfall in St. Louis. Rain falls for 8 days and accumulates 2.24" (57mm) of precipitation.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.
What is the least humid month?
April is the least humid month, with an average relative humidity of 63.5%.
What is the rainiest month?
The month with the most rainfall is May, when the rain falls for 11.9 days and typically aggregates up to 4.72" (120mm) of precipitation.
When it does not snow?
In St. Louis, snow does not fall in May through October.
When are the longest days?
June has the longest days of the year, with an average of 14h and 48min of daylight.
What are the months with the highest UV index?
The months with the highest UV index are June through August, with an average maximum UV index of 9.
What is the hottest time of year?
The month of July, characterized by an average high of 89.1°F (31.7°C) and a low of 71.1°F (21.7°C), is recognized as the warmest.
What month has the most sunshine?
July has the most sunshine of the year, with an average of 10h of sunshine.
What is the most humid month?
With an average relative humidity of 75.8%, December is the most humid month.
What is the month with the shortest days?
The month with the shortest days is December, with an average of 9h and 30min of daylight.
What is the month with the least sunshine?
With an average of 4.2h of sunshine, December has the least sunshine of the year in St. Louis.
Average temperature
St. Louis, MO
The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is January (39.9°F).
The month with the highest average low temperature is July (71°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).
Average humidity
St. Louis, MO
- Average humidity in January:
73% - Average humidity in February:
72% - Average humidity in March:
68.3% - Average humidity in April:
63.5% - Average humidity in May:
66.5% - Average humidity in June:
67.1%
The month with the highest relative humidity is December (75.8%).
The month with the lowest relative humidity is April (63.5%).
Average rainfall
St. Louis, MO
The wettest month (with the highest rainfall) is May (4.7").
The driest month (with the least rainfall) is February (2.2").
Average rainfall days
St. Louis, MO
- Average rainfall days in January:
8.9 days - Average rainfall days in February:
8 days - Average rainfall days in March:
10.3 days - Average rainfall days in April:
11.3 days - Average rainfall days in May:
11.9 days - Average rainfall days in June:
10 days
- Average rainfall days in July:
8.9 days - Average rainfall days in August:
8.2 days - Average rainfall days in September:
7.4 days - Average rainfall days in October:
8.7 days - Average rainfall days in November:
9.6 days - Average rainfall days in December:
9.4 days
The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is September (7.4 days).
Average snowfall
St. Louis, MO
The month with the highest snowfall is January (5.6").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days
St. Louis, MO
- Average snowfall days in January:
4.7 days - Average snowfall days in February:
3.4 days - Average snowfall days in March:
1.7 days - Average snowfall days in April:
0.3 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0.7 days - Average snowfall days in December:
3.7 days
The month with the highest number of snowfall days is January (4.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight / Average sunshine
St. Louis, MO
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 1min - Average daylight in May:
14h and 2min - Average daylight in June:
14h and 5min
- Average daylight in July:
14h and 4min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 1min - Average daylight in December:
9h and 3min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in January:
5h and 1min - Average sunshine in February:
5h and 4min - Average sunshine in March:
6h and 2min - Average sunshine in April:
7h and 3min - Average sunshine in May:
8h and 4min - Average sunshine in June:
9h and 4min
- Average sunshine in July:
10h and 0min - Average sunshine in August:
8h and 4min - Average sunshine in September:
7h and 5min - Average sunshine in October:
6h and 4min - Average sunshine in November:
4h and 4min - Average sunshine in December:
4h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).
Average UV index
St. Louis, MO
The months with the highest UV index are June, July and August (UV index 9).
The months with the lowest UV index are January and December (UV index 2).
