Climateby Month

St. Louis, MO climate by month

NOAA 1991-2020 normals · 464 ft elevation

Summers in St. Louis are hot and oppressively humid; winters are cold. Highs peak at 90°F in July and fall to 40°F in January. Wet days are spread through the year, from about 7 to 13 a month. Normal snowfall is about 17 in a year. The most comfortable time to visit is April and May.

Warmest month
90°F
July normal high
Coldest month
24°F
January normal low
Wet days a year
114
41.7 in of precipitation
Snow a year
16.6 in
normal snowfall

How warm is St. Louis?

Normal highs range from 40°F in January to 90°F in July.

20°40°60°80°100° January: normal high 40°F (4°C), low 24°F (-4°C) 40° 24° February: normal high 46°F (8°C), low 28°F (-2°C) March: normal high 57°F (14°C), low 37°F (3°C) April: normal high 68°F (20°C), low 47°F (8°C) May: normal high 77°F (25°C), low 58°F (14°C) June: normal high 86°F (30°C), low 67°F (19°C) July: normal high 90°F (32°C), low 71°F (22°C) 90° 71° August: normal high 88°F (31°C), low 69°F (21°C) September: normal high 81°F (27°C), low 61°F (16°C) October: normal high 69°F (21°C), low 49°F (9°C) November: normal high 56°F (13°C), low 37°F (3°C) December: normal high 45°F (7°C), low 29°F (-2°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is St. Louis?

May has the most wet days (about 13); the year brings about 42 in of precipitation.

January: 9 wet days February: 9 wet days March: 11 wet days April: 12 wet days May: 13 wet days 13 June: 10 wet days July: 9 wet days August: 8 wet days September: 7 wet days 7 October: 9 wet days November: 9 wet days December: 9 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 16.6 in a year, most of it in January.

January: 5.7 in of snow 5.7 February: 4.3 in of snow March: 2.3 in of snow April: 0.2 in of snow May: 0.0 in of snow 0.0 June: 0.0 in of snow July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 0.0 in of snow November: 0.9 in of snow December: 3.2 in of snow JFMAMJJASOND

How humid is St. Louis?

Muggy days peak in July, at about 21 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 4 muggy days June: 14 muggy days July: 21 muggy days 21 August: 19 muggy days September: 8 muggy days October: 1 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Lambert-St Louis International Airport, 13 mi NW of the city center.

How much daylight?

Daylight ranges from about 9.5 hours in December to 14.8 hours in June.

January: 9.8 hours of daylight February: 10.8 hours of daylight March: 12.0 hours of daylight April: 13.2 hours of daylight May: 14.3 hours of daylight June: 14.8 hours of daylight 14.8 July: 14.6 hours of daylight August: 13.6 hours of daylight September: 12.4 hours of daylight October: 11.2 hours of daylight November: 10.1 hours of daylight December: 9.5 hours of daylight 9.5 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for St. Louis, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 40°F24°F 2.6 in9 5.7 in 0 9.8 h
February 46°F28°F 2.2 in9 4.3 in 0 10.8 h
March 57°F37°F 3.5 in11 2.3 in 0 12.0 h
April 68°F47°F 4.7 in12 0.2 in 0 13.2 h
May 77°F58°F 4.8 in13 0.0 in 4 14.3 h
June 86°F67°F 4.5 in10 0.0 in 14 14.8 h
July 90°F71°F 3.9 in9 0.0 in 21 14.6 h
August 88°F69°F 3.4 in8 0.0 in 19 13.6 h
September 81°F61°F 3.0 in7 0.0 in 8 12.4 h
October 69°F49°F 3.1 in9 0.0 in 1 11.2 h
November 56°F37°F 3.4 in9 0.9 in 0 10.1 h
December 45°F29°F 2.5 in9 3.2 in 0 9.5 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit St. Louis

By our comfort score, the best months are April and May.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 341517
Feb 423511
Mar 55873
Apr 671380
May 661282
Jun 524711
Jul 451616
Aug 472513
Sep 601055
Oct 631461
Nov 50754
Dec 362512

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in St. Louis

The last spring frost typically comes around Apr 8, and the first fall frost around Oct 26, leaving 200 frost-free days in a typical year.

Frost and freeze dates for St. Louis
Typical date1 year in 10
Last spring frost (32°F)Apr 8after Apr 23
First fall frost (32°F)Oct 26before Oct 12
Last hard freeze (28°F)Mar 28after Apr 12
First hard freeze (28°F)Nov 6before Oct 24
Frost-free season200 daysunder 180 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Cahokia St Louis Airport (USW00003960), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Missouri.

Hottest and coldest readings, 1991-2020

The highest reading was 108°F (June 28, 2012); the lowest was -12°F (February 3, 1996).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near St. Louis

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth, humidity and wind by hour and cloud cover: St Louis Lambert Intl Airport (USW00013994), 13 mi NW of the city center, 531 ft (67 ft higher than the city). NOAA normals and daily records, 1991-2020.
  • Frost dates: Cahokia St Louis Airport (USW00003960), 4.4 mi SSE of the city center, 413 ft (51 ft lower than the city). NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Lambert-St Louis International Airport (724340-13994), 13 mi NW of the city center, 531 ft (67 ft higher than the city). Hourly observations, 1991-2020.

Distances from the city center (USGS). Methodology · Report an error