What is the hottest month in Affton, MO?

July is the warmest month, with a normal high of 90°F at St Louis Sci Ctr.

What is the coldest month in Affton, MO?

January is the coldest month, with a normal low of 25°F.

What is the wettest month in Affton, MO?

May has the most precipitation on average, about 4.90 inches.

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Checked Oct 25, 2026

Affton, MO Climate

1991 to 2020 normals at St Louis Sci Ctr, 6.5 mi from the center of Affton, elevation 515 ft.

Average weather by month

Select a month for daily normals and last year's weather

Month	High	Low	Precip.	Snow
January	41°	25°	2.71 in	--
February	46°	28°	2.28 in	--
March	56°	38°	3.61 in	--
April	68°	48°	4.83 in	--
May	77°	59°	4.90 in	--
June	86°	67°	4.74 in	--
July	90°	72°	4.21 in	--
August	89°	70°	3.75 in	--
September	82°	62°	3.41 in	--
October	70°	50°	3.20 in	--
November	56°	39°	3.69 in	--
December	45°	30°	2.58 in	--
Year	67°		43.91 in	--

Frequently asked questions

What is the hottest month in Affton, MO?: July is the warmest month, with a normal high of 90°F at St Louis Sci Ctr.
What is the coldest month in Affton, MO?: January is the coldest month, with a normal low of 25°F.
What is the wettest month in Affton, MO?: May has the most precipitation on average, about 4.90 inches.

Today

Affton, MO forecast

Data sources

U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information · Official site
U.S. Climate Normals 1991-2020 (daily) and GHCN-Daily via Access Data ServiceNOAA National Centers for Environmental Information · Official site

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About this data

Weather and emergencies: Weather, air quality and hazard information on this page is delayed and may be incomplete. It is not a substitute for official warnings. Always follow the National Weather Service, local emergency management and public safety officials. In an emergency, call 911. For evacuation orders, use your local official alert system.

Climate normals are 30-year averages measured at one weather station, which may be miles from the place named here or at a different elevation.

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