Thornton climate

Thornton Weather in September

NOAA 1991-2020 normals for Marlin, 31.2 km from Thornton

Average highs run from 93°F on September 1 to 86°F on September 30, and lows from 68°F to 60°F. Normal precipitation for the month is 3.05 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 Thornton, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
90°F
Average low
64°F
Precipitation
3.05 in
Record high
110°FSep 3, 2000
Record low
38°FSep 25, 1989
Chance of a freeze
0%
Days of 90°F or more
17.5
Daylight
12 h 48 min to 11 h 52 min
Cloud cover
43%
Humidity
65%
Dew point
64°F
Wind
7.6 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 193°F68°F109°F 200060°F 200416%0%
Sep 293°F68°F107°F 200057°F 198716%0%
Sep 393°F68°F110°F 200056°F 197417%0%
Sep 493°F67°F110°F 200052°F 197417%0%
Sep 593°F67°F108°F 200051°F 197417%0%
Sep 692°F67°F102°F 199051°F 197417%0%
Sep 792°F67°F102°F 196354°F 200317%0%
Sep 892°F66°F103°F 199057°F 200417%0%
Sep 992°F66°F101°F 198952°F 200417%0%
Sep 1091°F66°F100°F 198258°F 198817%0%
Sep 1191°F66°F100°F 198255°F 196817%0%
Sep 1291°F65°F102°F 198257°F 196817%0%
Sep 1391°F65°F101°F 198256°F 196917%0%
Sep 1490°F65°F100°F 198453°F 200617%0%
Sep 1590°F64°F102°F 198049°F 198917%0%
Sep 1690°F64°F100°F 198050°F 198917%0%
Sep 1790°F64°F100°F 198049°F 200017%0%
Sep 1889°F64°F99°F 198049°F 200017%0%
Sep 1989°F63°F99°F 198053°F 199417%0%
Sep 2089°F63°F98°F 198850°F 197117%0%
Sep 2188°F63°F99°F 200547°F 199117%0%
Sep 2288°F62°F100°F 200540°F 198317%0%
Sep 2388°F62°F99°F 200542°F 199417%0%
Sep 2488°F62°F98°F 200046°F 198517%0%
Sep 2587°F61°F101°F 200538°F 198916%0%
Sep 2687°F61°F104°F 200541°F 200016%0%
Sep 2787°F61°F103°F 200543°F 200016%0%
Sep 2887°F60°F98°F 200539°F 196716%0%
Sep 2986°F60°F98°F 200544°F 196716%0%
Sep 3086°F60°F95°F 197739°F 198416%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Thornton, 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 (CDT).

September 1
sunrise 7:02 AM, sunset 7:50 PM
September 30
sunrise 7:20 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 USC00415611 (Marlin), public domain. Records: NOAA GHCN-Daily, station USC00413047, 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.