Jefferson County climate

Jefferson County Weather in September

NOAA 1991-2020 normals for Oskaloosa 4 Ne, 9.5 km from Jefferson County

Average highs run from 85°F on September 1 to 75°F on September 30, and lows from 62°F to 51°F. Normal precipitation for the month is 3.36 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 Jefferson County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
80°F
Average low
57°F
Precipitation
3.36 in
Record high
110°FSep 3, 1947
Record low
29°FSep 23, 1983
Chance of a freeze
5%
Days of 90°F or more
3.0
Daylight
13 h 02 min to 11 h 48 min
Cloud cover
45%
Humidity
68%
Dew point
56°F
Wind
9.8 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 185°F62°F106°F 201144°F 194923%0%
Sep 284°F62°F109°F 200048°F 194923%0%
Sep 384°F62°F110°F 194744°F 197423%0%
Sep 484°F61°F103°F 195439°F 197423%0%
Sep 583°F61°F101°F 202640°F 197424%0%
Sep 683°F61°F100°F 199841°F 198824%0%
Sep 783°F60°F106°F 194742°F 195624%0%
Sep 882°F60°F104°F 201341°F 198624%0%
Sep 982°F59°F101°F 197042°F 197624%0%
Sep 1082°F59°F100°F 198436°F 197624%0%
Sep 1182°F59°F104°F 200039°F 195924%0%
Sep 1281°F58°F103°F 195641°F 195924%0%
Sep 1381°F58°F99°F 195638°F 201424%0%
Sep 1481°F57°F96°F 202637°F 197424%0%
Sep 1580°F57°F94°F 195539°F 196124%0%
Sep 1680°F57°F101°F 197841°F 196124%0%
Sep 1780°F56°F103°F 195339°F 198124%0%
Sep 1879°F56°F99°F 202235°F 197324%0%
Sep 1979°F55°F99°F 202235°F 199124%0%
Sep 2079°F55°F100°F 202236°F 199124%0%
Sep 2178°F55°F98°F 195636°F 198223%0%
Sep 2278°F54°F95°F 198831°F 199523%0%
Sep 2378°F54°F92°F 198429°F 198323%0%
Sep 2477°F53°F93°F 198431°F 198923%0%
Sep 2577°F53°F92°F 199033°F 198923%0%
Sep 2677°F53°F96°F 199032°F 197523%0%
Sep 2776°F52°F94°F 202135°F 198922%0%
Sep 2876°F52°F104°F 195334°F 198922%0%
Sep 2976°F51°F95°F 195232°F 198422%0%
Sep 3075°F51°F94°F 202329°F 198422%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Jefferson 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 6:50 AM, sunset 7:52 PM
September 30
sunrise 7:17 AM, sunset 7:05 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00146100 (Oskaloosa 4 Ne), public domain. Records: NOAA GHCN-Daily, station USW00013996, 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.