30-year climate normals

St. Louis city Climate and Weather Averages

Hottest month — July

89.6°

average daily high. The coldest month is January, averaging a low of 24.6°F.

St. Louis city gets 43.91" of precipitation a year, and 33% of it falls in Apr, May, Jun.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	40.6°	24.6°	2.71"
February	46.2°	28.4°	2.28"
March	56.3°	37.8°	3.61"
April	67.7°	48.0°	4.83"
May	77.3°	58.6°	4.90"
June	86.0°	67.4°	4.74"
July	89.6°	71.6°	4.21"
August	88.5°	69.9°	3.75"
September	81.5°	61.7°	3.41"
October	69.7°	50.0°	3.20"
November	56.2°	39.0°	3.69"
December	45.0°	29.9°	2.58"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 33% falling in the wettest three months (Apr, May, Jun).

January 2.71"

February 2.28"

March 3.61"

April 4.83"

May 4.90"

June 4.74"

July 4.21"

August 3.75"

September 3.41"

October 3.20"

November 3.69"

December 2.58"

Annual total 43.91"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 1,769

Heating degree days How much heating the climate demands 4,292

Approximate annual cooling cost At 13.68¢/kWh, Missouri average $242

Approximate annual electric heating cost Lower where heating is gas rather than electric $206

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in St. Louis city, where electricity is one line of eight.

Common questions

What is the weather like in St. Louis city?

St. Louis city averages a high of 89.6°F in July and a low of 24.6°F in January. Annual precipitation is 43.91 inches, with essentially no snow.

When is the rainy season in St. Louis city?

The wettest stretch is Apr, May, Jun, which accounts for 33% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in St. Louis city?

The average daily high in July, the hottest month, is 89.6°F. That drives 1,769 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in St. Louis city?

Effectively no. Measurable snowfall is rare in St. Louis city.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station ST LOUIS SCI CTR, MO US (USC00237452), 1.5 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Missouri residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.