Lemhi County climate

Lemhi County Weather in September

NOAA 1991-2020 normals for Salmon-Ksra, 25.9 km from Lemhi County

Average highs run from 80°F on September 1 to 68°F on September 30, and lows from 45°F to 36°F. Normal precipitation for the month is 0.79 in over about 5 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 Lemhi County, in °F, with the record for each date.020406080100151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
74°F
Average low
41°F
Precipitation
0.79 in
Record high
98°FSep 6, 2020
Record low
20°FSep 30, 1985
Chance of a freeze
72%
Days of 90°F or more
1.3
Daylight
13 h 14 min to 11 h 45 min
Cloud cover
48%
Humidity
50%
Dew point
31°F
Wind
5.1 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 180°F45°F96°F 199135°F 196917%0%
Sep 280°F44°F95°F 196933°F 197416%0%
Sep 379°F44°F97°F 198835°F 197516%0%
Sep 479°F44°F93°F 202533°F 196916%0%
Sep 579°F44°F97°F 201934°F 196916%0%
Sep 678°F43°F98°F 202032°F 196916%0%
Sep 778°F43°F93°F 197728°F 199216%0%
Sep 878°F43°F97°F 202229°F 202016%0%
Sep 977°F43°F92°F 198129°F 197616%0%
Sep 1077°F42°F91°F 198129°F 202016%0%
Sep 1176°F42°F89°F 198132°F 200516%0%
Sep 1276°F42°F91°F 198129°F 201416%0%
Sep 1376°F41°F90°F 198129°F 197416%0%
Sep 1475°F41°F90°F 199027°F 197017%0%
Sep 1575°F41°F95°F 200026°F 197017%0%
Sep 1674°F41°F94°F 199028°F 197017%0%
Sep 1774°F40°F90°F 198129°F 202117%0%
Sep 1874°F40°F91°F 198125°F 197117%0%
Sep 1973°F40°F89°F 197926°F 197117%0%
Sep 2073°F39°F92°F 200921°F 198317%0%
Sep 2172°F39°F89°F 197926°F 197117%0%
Sep 2272°F39°F86°F 197924°F 197117%0%
Sep 2371°F39°F96°F 202425°F 199617%0%
Sep 2471°F38°F87°F 198727°F 197217%0%
Sep 2570°F38°F90°F 201422°F 197017%0%
Sep 2670°F38°F91°F 202423°F 197217%0%
Sep 2769°F37°F86°F 202428°F 197017%0%
Sep 2869°F37°F86°F 201122°F 199917%0%
Sep 2968°F37°F86°F 202422°F 198517%0%
Sep 3068°F36°F86°F 202420°F 198517%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Lemhi County, in percent, and of at least 0.1 inch of snowfall.051015201102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (MDT).

September 1
sunrise 6:58 AM, sunset 8:12 PM
September 30
sunrise 7:33 AM, sunset 7:18 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00108080 (Salmon-Ksra), public domain. Records: NOAA GHCN-Daily, station USC00108080, 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.