St. Clair County climate

St. Clair County Weather in September

NOAA 1991-2020 normals for Osceola, 6.5 km from St. Clair County

Average highs run from 86°F on September 1 to 76°F on September 30, and lows from 63°F to 52°F. Normal precipitation for the month is 4.02 in over about 7 wet days.

September day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at St. Clair County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
81°F
Average low
58°F
Precipitation
4.02 in
Record high
108°FSep 4, 1913
Record low
29°FSep 24, 1989
Chance of a freeze
2%
Days of 90°F or more
5.0
Daylight
12 h 59 min to 11 h 49 min
Cloud cover
45%
Humidity
69%
Dew point
58°F
Wind
6.9 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
Sep 186°F63°F105°F 192246°F 198723%0%
Sep 285°F62°F105°F 191343°F 195223%0%
Sep 385°F62°F107°F 191343°F 197423%0%
Sep 485°F62°F108°F 191339°F 197423%0%
Sep 585°F61°F106°F 191341°F 197423%0%
Sep 684°F61°F107°F 193638°F 198823%0%
Sep 784°F61°F106°F 194738°F 198824%0%
Sep 884°F60°F105°F 194740°F 195624%0%
Sep 983°F60°F103°F 193942°F 194324%0%
Sep 1083°F60°F102°F 193642°F 197624%0%
Sep 1183°F59°F103°F 193639°F 194024%0%
Sep 1282°F59°F101°F 193638°F 194024%0%
Sep 1382°F59°F103°F 193138°F 201424%0%
Sep 1482°F58°F102°F 193142°F 196024%0%
Sep 1581°F58°F103°F 193140°F 196124%0%
Sep 1681°F57°F98°F 193140°F 191824%0%
Sep 1780°F57°F100°F 193340°F 191824%0%
Sep 1880°F57°F102°F 193138°F 198124%0%
Sep 1980°F56°F98°F 193135°F 199124%0%
Sep 2079°F56°F101°F 195435°F 199123%0%
Sep 2179°F55°F98°F 193134°F 191823%0%
Sep 2279°F55°F99°F 193731°F 199523%0%
Sep 2378°F55°F96°F 193731°F 199523%0%
Sep 2478°F54°F95°F 193529°F 198923%0%
Sep 2578°F54°F92°F 193929°F 198923%0%
Sep 2677°F53°F95°F 193831°F 191223%0%
Sep 2777°F53°F94°F 192930°F 194223%0%
Sep 2877°F53°F103°F 195333°F 190823%0%
Sep 2976°F52°F97°F 195332°F 195723%0%
Sep 3076°F52°F93°F 193830°F 198423%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at St. Clair County, in percent, and of at least 0.1 inch of snowfall.05101520251102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

September 1
sunrise 6:45 AM, sunset 7:44 PM
September 30
sunrise 7:10 AM, sunset 6:59 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00236402 (Osceola), public domain. Records: NOAA GHCN-Daily, station USC00231711, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.