Weather in St. Louis: Climate, Seasons, and Average Monthly Temperature

Kiener Plaza
gnagel / Getty Images

Missouri writer Mark Twain once famously said, “If you don’t like the weather in New England, just wait a few minutes.” These words could also easily refer to St. Louis, Missouri, where it’s possible to experience several types of weather in just one day.

St. Louis has four seasons: hot, humid summers; wet, cool falls; cold, damp winters; and even wetter springs. However, it’s not uncommon to get a 60 degree day in January, as the day-to-day weather is greatly impacted by fronts that move in from other parts of the country.

Due to its flat, inland location, St. Louis receives its fair share of extreme weather, including summertime highs, wintertime lows, tornadoes, and flooding — although the latter rarely affects visitors. Here’s what you need to know about the weather when planning your trip to St. Louis.

Fast Climate Facts

  • Hottest Month: July (87 degrees Fahrenheit/27 degrees Celsius)
  • Coldest Month: January (39 degrees Fahrenheit/4 degrees Celsius)
  • Wettest Month: May (4.90 inches)

Tornado Season in St. Louis

St. Louis lies in the unofficial area known as “Tornado Alley,” which includes the Great Plains, the Midwest, and parts of the South. Although most tornadoes occur in the spring, severe weather can happen in the area during any season. While the risk exists, tornadoes are rare and tend to do localized damage, so they shouldn’t be a reason to put off your visit. If you hear the tornado siren, seek shelter in an interior room away from windows and doors and check the local news for more information. The tornado sirens in both St. Louis city and the county are tested on the first Monday morning of the month, weather permitting.

Summer in St. Louis

There’s no denying that St. Louis summers are hot and sticky. It’s not unusual for there to be several days each year, usually in July and August, that reach 100 degrees F (38 degrees C). With the high humidity, some days can feel downright oppressive. June and July tend to be fairly wet months, averaging 4.60 and 4.48 inches of rain respectively, but there are plenty of sunny days that are perfect for a visit to the Saint Louis Zoo or for taking in a Cardinals baseball game. Despite the heat, this is a popular time for families to visit.

What to pack: Shorts and T-shirts are typical summer attire and are appropriate at most family attractions. Area pools are open Memorial Day through Labor Day, so bring a swimming suit and sunscreen if you plan to swim.

Average Temperatures by Month

June: 83 F (28 C) / 63 F (17 C)

July: 87 F (31 C) / 67 F (19 C)

August: 86 F (30 C) / 65 F (18 C)

Fall in St. Louis 

Area children return to school in mid-to-late August, signaling that the end of summer’s stifling heat is near. As fall progresses, cooler temperatures and crisp air prevail, and soon the trees are sporting brilliant red, yellow, and oranges leaves. Although fall has almost as much rain as spring (starting at 3.72 inches in September and increasing each month), there are many clear days with blue skies, making it an ideal time to visit.

As with every season in St. Louis, the weather can be somewhat unpredictable, depending on what’s happening in other parts of the country. It’s not completely unheard of for there to be an early snow on Halloween.

What to pack: Layering is key when planning for St. Louis weather. It gets chilly at night, especially toward the end of fall, so bring long-sleeve shirts and a rain jacket.

Average Temperatures by Month

September: 79 F (26 C) / 56 F (13 C)

October: 68 F (20 C) / 45 F (7 C)

November: 56 F (13 C) / 36 F (2 C)

Winter in St. Louis 

During a winter visit to St. Louis, be prepared for cold, dreary days. Most days are cloudy or partly cloudy, and the year-round humidity can make it feel chilly and damp. St. Louis gets an average of 16 inches of snow a year, although this varies from year to year. Most winter precipitation occurs between the months of December and March, and snowstorms and freezing rain can bring traffic to a halt.

Despite this, many area attractions — even the outdoor ones — are open throughout the year, so you won’t run out of things to do. 

What to pack: Warm clothes are a must for winter in St. Louis. Bring a warm winter coat, hat, and gloves, and consider long underwear if you plan to spend a lot of time outside.

Average Temperatures by Month

December: 42 F (6 C) / 24 F (-4 C)

January: 39 F (4 C) / 20 F (-7 C)

February: 45 F (7 C) / 24 F (-4 C)

Spring in St. Louis 

Spring is a lovely — and often unpredictable — time of year in St. Louis. The area gets approximately 42 inches of precipitation a year, much of that in the spring. It’s not unusual for it to rain several days in a row, although it rarely rains all day. Spring storms also bring the possibility for extreme weather, including hail and tornadoes. Despite the storms and the variable temperatures, the daffodils, dogwoods, and other plants bloom throughout these months, making it a favorite season for many St. Louisans. 

What to pack: Temperatures can vary widely throughout the day, so bring clothing that can be layered. An umbrella or rain jacket also comes in handy.

Average Temperatures by Month

March: 55 F (13 C) / 33 F (1 C)

April: 67 F (19 C) / 44 F (7 C)

May: 75 F (24 C) / 54 F (12 C)

Average Monthly Temperature, Rainfall, and Daylight Hours

Average Monthly Temperature, Rainfall, and Daylight Hours
Month Avg. Temp. Rainfall Daylight Hours
January 32 F (0 C) 2.4 in 10 hours
February 36 F (2 C) 2.24 in 11 hours
March 46 F (8 C) 3.3 in 12 hours
April 57 F (14 C) 3.69 in 13 hours
May 67 F (19 C) 4.72 in 14 hours
June 76 F (24 C) 4.28 in 15 hours
July 80 F (27 C) 4.11 in 15 hours
August 79 F (26 C) 2.99 in 14 hours
September 70 F (21 C) 3.13 in 12 hours
October 59 F (15 C) 3.33 in 11 hours
November 47 F (8 C) 3.91 in 10 hours
December 35 F (2 C) 2.84 in 10 hours
Article Sources
TripSavvy uses only high-quality, trusted sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we keep our content accurate, reliable and trustworthy.
  1. Britannica. "Climate Lake Saint Louis - Missouri and weather averages." December 2020.

  2. "St. Louis, Missouri Climate." December 2020.