Weather
St. Louis, MO Weather Oct. 16–20: 40s Arrive, Then Near 80
ST. LOUIS, MO — A sharp October cooldown will bring chilly nights to the St. Louis area beginning Friday, Oct. 16, before several days of sunshine send afternoon temperatures climbing toward 80 degree
By Nolan Pierce · 2026-10-14T09:35:46.422Z
ST. LOUIS, MO — A sharp October cooldown will bring chilly nights to the St. Louis area beginning Friday, Oct. 16, before several days of sunshine send afternoon temperatures climbing toward 80 degrees by Tuesday.
According to the National Weather Service, temperatures near the Mississippi River in the St. Louis metropolitan area are expected to fall from a high of 83 degrees Thursday to just 61 degrees Friday, a 22 degree drop in daytime temperatures.
The change follows a stretch of unsettled weather, with showers and thunderstorms expected Wednesday and Thursday before cooler, drier conditions arrive.
Temperatures Drop 22 Degrees Before Chilly Weekend Nights The National Weather Service expects showers and possibly a thunderstorm Thursday, with an 80% chance of precipitation.
Rain chances continue Thursday night before conditions improve Friday.
The approaching weather system will bring a significant temperature change, replacing Thursday's warmth with afternoon highs in the lower 60s.
By Friday night, temperatures are expected to fall to around 41 degrees under mostly clear skies.
Saturday will remain relatively cool, with sunshine and a high near 62 degrees before another overnight low around 41.
Those readings represent a substantial shift from the warmer conditions earlier in the week, particularly for residents spending time outdoors during the early morning and evening hours.
NOAA's Weather Prediction Center has identified a broader pattern change across the central United States as strong high pressure moves south from Canada.
Although some locations farther north could approach freezing, the supplied St. Louis area forecast keeps overnight temperatures above freezing.
Sunshine Brings a Steady Warmup The cooler conditions will not last long.
Sunday brings sunny skies and a high near 69 degrees, beginning a gradual warming trend that continues into the new workweek.
Monday's high is expected to reach 73 degrees under mostly sunny skies, with overnight temperatures becoming milder.
By Tuesday, temperatures could reach 77 degrees, approximately 16 degrees warmer than Friday's expected high.
The five day outlook contains no additional rain chances from Friday through Tuesday, offering a prolonged stretch of favorable weather following the midweek storms.
For residents across the St. Louis metropolitan area, the forecast points toward a brief but noticeable taste of fall before warmer afternoons return.
Five Day Weather Outlook: Oct. 16–20 Temperatures below represent the National Weather Service forecast for the St. Louis metropolitan area, specifically a location approximately 2 miles west southwest of Brooklyn, Illinois, near the Mississippi River.
Friday, Oct. 16: Mostly sunny and significantly cooler, with a high near 61°F. Mostly clear overnight, with temperatures falling to around 41°F. Saturday, Oct. 17: Sunny, with a high near 62°F. Clear overnight, with another low around 41°F. Sunday, Oct. 18: Sunny and warmer, with a high near 69°F. Partly cloudy overnight, with a low around 47°F. Monday, Oct. 19: Mostly sunny, with a high near 73°F. Partly cloudy overnight, with a low around 51°F. Tuesday, Oct. 20: Mostly sunny and warmer, with a high near 77°F.