St. Clair County climate

St. Clair County Weather in September

NOAA 1991-2020 normals for Oneonta, 25.4 km from St. Clair County

Average highs run from 88°F on September 1 to 81°F on September 30, and lows from 67°F to 58°F. Normal precipitation for the month is 4.09 in over about 6 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
85°F
Average low
63°F
Precipitation
4.09 in
Record high
109°FSep 6, 1925
Record low
35°FSep 30, 1967
Chance of a freeze
0%
Days of 90°F or more
6.6
Daylight
12 h 52 min to 11 h 52 min
Cloud cover
49%
Humidity
70%
Dew point
62°F
Wind
4.0 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 188°F67°F102°F 195152°F 194622%0%
Sep 288°F67°F101°F 195752°F 195422%0%
Sep 388°F67°F104°F 192553°F 195221%0%
Sep 488°F66°F106°F 192550°F 195221%0%
Sep 587°F66°F108°F 192550°F 193421%0%
Sep 687°F66°F109°F 192550°F 199720%0%
Sep 787°F66°F106°F 192543°F 198420%0%
Sep 887°F65°F104°F 192549°F 201720%0%
Sep 987°F65°F107°F 192548°F 195820%0%
Sep 1086°F65°F102°F 192542°F 197620%0%
Sep 1186°F64°F98°F 192747°F 196919%0%
Sep 1286°F64°F98°F 192743°F 194019%0%
Sep 1386°F64°F101°F 192745°F 194019%0%
Sep 1486°F63°F100°F 192742°F 190219%0%
Sep 1585°F63°F102°F 192746°F 201519%0%
Sep 1685°F63°F101°F 192746°F 190419%0%
Sep 1785°F62°F102°F 192745°F 199919%0%
Sep 1885°F62°F102°F 193140°F 198119%0%
Sep 1984°F62°F103°F 192540°F 198119%0%
Sep 2084°F61°F103°F 192540°F 198119%0%
Sep 2184°F61°F100°F 192541°F 191819%0%
Sep 2283°F61°F101°F 192540°F 191319%0%
Sep 2383°F60°F100°F 193138°F 199919%0%
Sep 2483°F60°F98°F 192139°F 199919%0%
Sep 2583°F60°F99°F 193138°F 199019%0%
Sep 2682°F59°F97°F 201638°F 200119%0%
Sep 2782°F59°F97°F 190437°F 189919%0%
Sep 2882°F58°F99°F 190436°F 189919%0%
Sep 2981°F58°F101°F 190439°F 196719%0%
Sep 3081°F58°F99°F 190435°F 196718%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 6:19 AM, sunset 7:11 PM
September 30
sunrise 6:39 AM, sunset 6:31 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00016121 (Oneonta), public domain. Records: NOAA GHCN-Daily, station USC00018024, 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.