Dewey County climate

Dewey County Weather in September

NOAA 1991-2020 normals for Timber Lake, 34.1 km from Dewey County

Average highs run from 82°F on September 1 to 69°F on September 30, and lows from 54°F to 42°F. Normal precipitation for the month is 1.53 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 Dewey County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
76°F
Average low
48°F
Precipitation
1.53 in
Record high
102°FSep 7, 2002
Record low
25°FSep 24, 2000
Chance of a freeze
54%
Days of 90°F or more
2.9
Daylight
13 h 16 min to 11 h 44 min
Cloud cover
51%
Humidity
56%
Dew point
45°F
Wind
11.0 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 182°F54°F101°F 201246°F 200521%0%
Sep 282°F53°F101°F 202340°F 200821%0%
Sep 381°F53°F99°F 200537°F 200821%0%
Sep 481°F53°F99°F 200541°F 201121%0%
Sep 581°F52°F100°F 200136°F 202521%0%
Sep 680°F52°F97°F 200234°F 202521%0%
Sep 780°F52°F102°F 200238°F 200421%0%
Sep 880°F51°F94°F 202237°F 200821%
Sep 979°F51°F94°F 202431°F 202021%
Sep 1079°F50°F101°F 199838°F 202021%
Sep 1179°F50°F92°F 200538°F 201521%
Sep 1278°F50°F97°F 201738°F 201421%
Sep 1378°F49°F94°F 201536°F 201221%
Sep 1477°F49°F93°F 200634°F 201421%
Sep 1577°F49°F93°F 201537°F 201121%
Sep 1676°F48°F95°F 200241°F 201021%
Sep 1776°F48°F94°F 199837°F 201021%
Sep 1875°F47°F97°F 199833°F 200321%
Sep 1975°F47°F93°F 200432°F 200321%
Sep 2074°F47°F91°F 200534°F 200621%
Sep 2174°F46°F94°F 201530°F 201121%
Sep 2273°F46°F92°F 201326°F 201221%
Sep 2373°F45°F89°F 200728°F 200021%
Sep 2472°F45°F87°F 201425°F 200021%
Sep 2572°F44°F93°F 201429°F 200021%
Sep 2671°F44°F99°F 202426°F 200221%
Sep 2771°F43°F90°F 202134°F 199921%
Sep 2870°F43°F95°F 202432°F 200621%
Sep 2969°F43°F99°F 202431°F 200321%
Sep 3069°F42°F90°F 200526°F 200321%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Dewey 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 (MDT).

September 1
sunrise 6:05 AM, sunset 7:21 PM
September 30
sunrise 6:41 AM, sunset 6:25 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00398307 (Timber Lake), public domain. Records: NOAA GHCN-Daily, station USW00094052, 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 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.