St. Louis, MO Weather Forecast & Climate Guide
St. Louis has a humid continental climate with hot summers and cold winters near Tornado Alley.
Climate type: Humid continental (Köppen Dfa)
St. Louis Climate Overview
Hot, humid summers with severe weather potential. Cold winters with ice and snow.
Severe thunderstorms and tornadoes possible in spring. Summer heat waves common.
St. Louis Weather by Season
spring
Spring is wet and stormy — this is peak severe weather season. April and May bring large hail, tornadoes, and flooding rains, but also pleasant mild temperatures and blooming flowers.
summer
Summers are hot and humid with highs in the upper 80s°F and frequent heat waves. St. Louis routinely sees some of the highest heat index values in the Midwest.
fall
Fall is beautiful with crisp September days in the 70s°F, vivid October foliage, and mild November weather. Low humidity and minimal storms make it the best outdoor season.
winter
Winters are cold and variable with highs in the low 40s°F and occasional ice storms. Arctic outbreaks can push temperatures below zero.
St. Louis Average Monthly Temperatures
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 40° | 45° | 56° | 67° | 76° | 85° | 89° | 87° | 80° | 68° | 54° | 42° |
| Low °F | 23° | 27° | 36° | 46° | 56° | 65° | 70° | 68° | 60° | 48° | 36° | 27° |
Best Time to Visit St. Louis
September through October for mild, dry, sunny weather and fall foliage. Late April through May is also lovely but carries severe weather risk.
Severe Weather Risks
- Tornadoes
- Severe thunderstorms
- Ice storms
- Flash flooding
- Heat waves
Weather Facts About St. Louis
- >St. Louis sits at the confluence of the Missouri and Mississippi rivers — and at the eastern edge of Tornado Alley.
- >The 1896 St. Louis Tornado killed over 250 people, one of the deadliest in US history.
- >The city is known for some of the highest heat index values in the Midwest due to its river valley humidity.
St. Louis Weather FAQ
When is the best time to visit St. Louis?
September through October delivers the best weather — mild days in the 70s°F, low humidity, minimal storm risk, and fall color. April-May is also pleasant but with significant severe weather risk.
Does St. Louis get tornadoes?
Yes. St. Louis sits at the eastern edge of Tornado Alley and sees multiple severe weather outbreaks each spring. The historic 1896 tornado killed over 250 people, and modern outbreaks regularly threaten the metro.
How hot does St. Louis get in summer?
Very hot. July and August average highs in the upper 80s°F with frequent 90°F+ days. High humidity pushes heat index values past 105°F regularly during heat waves.
Does St. Louis get flooding?
Yes. The confluence of the Missouri and Mississippi rivers makes the metro area vulnerable to major flooding. The 1993 flood was one of the worst in US history, with levees failing and entire neighborhoods underwater.