Jefferson County climate

Jefferson County Weather in September

NOAA 1991-2020 normals for Hamer 4 Nw, 16.7 km from Jefferson County

Average highs run from 83°F on September 1 to 71°F on September 30, and lows from 43°F to 35°F. Normal precipitation for the month is 0.63 in over about 4 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.020406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
78°F
Average low
39°F
Precipitation
0.63 in
Record high
100°FSep 3, 2022
Record low
18°FSep 20, 1983
Chance of a freeze
96%
Days of 90°F or more
1.3
Daylight
13 h 12 min to 11 h 46 min
Cloud cover
44%
Humidity
45%
Dew point
34°F
Wind
6.7 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 183°F43°F96°F 202232°F 196512%0%
Sep 283°F43°F96°F 195033°F 197512%0%
Sep 383°F42°F100°F 202230°F 196412%0%
Sep 482°F42°F97°F 202231°F 196512%0%
Sep 582°F42°F97°F 202033°F 196513%0%
Sep 682°F41°F99°F 202231°F 201013%0%
Sep 781°F41°F99°F 202230°F 199213%0%
Sep 881°F41°F92°F 202129°F 200113%0%
Sep 980°F41°F95°F 202126°F 196213%0%
Sep 1080°F40°F95°F 195929°F 202013%0%
Sep 1180°F40°F93°F 199032°F 196413%0%
Sep 1279°F40°F91°F 199024°F 201413%0%
Sep 1379°F40°F91°F 194829°F 198913%0%
Sep 1479°F39°F94°F 199028°F 199314%0%
Sep 1578°F39°F91°F 200026°F 197014%0%
Sep 1678°F39°F89°F 200029°F 196514%0%
Sep 1777°F39°F90°F 201424°F 196514%0%
Sep 1877°F38°F90°F 195621°F 196514%0%
Sep 1976°F38°F90°F 195622°F 196514%0%
Sep 2076°F38°F86°F 202218°F 198314%0%
Sep 2175°F38°F86°F 196622°F 198314%0%
Sep 2275°F37°F87°F 196625°F 197114%0%
Sep 2374°F37°F88°F 198723°F 198514%0%
Sep 2474°F37°F88°F 198718°F 200013%0%
Sep 2573°F36°F89°F 200121°F 197013%0%
Sep 2673°F36°F87°F 196326°F 197013%0%
Sep 2772°F36°F86°F 196924°F 196413%0%
Sep 2872°F35°F89°F 202418°F 199913%0%
Sep 2971°F35°F89°F 195718°F 198513%0%
Sep 3071°F35°F90°F 195718°F 198513%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.0510151102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (MDT).

September 1
sunrise 6:53 AM, sunset 8:05 PM
September 30
sunrise 7:26 AM, sunset 7:12 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00103964 (Hamer 4 Nw), public domain. Records: NOAA GHCN-Daily, station USW00024145, 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.