Knox County climate

Knox County Weather in September

NOAA 1991-2020 normals for Vincennes 5 Ne, 8.2 km from Knox County

Average highs run from 86°F on September 1 to 77°F on September 30, and lows from 62°F to 51°F. Normal precipitation for the month is 3.63 in over about 8 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 Knox County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
82°F
Average low
57°F
Precipitation
3.63 in
Record high
104°FSep 5, 2026
Record low
34°FSep 24, 2012
Chance of a freeze
2%
Days of 90°F or more
5.8
Daylight
13 h 01 min to 11 h 49 min
Cloud cover
46%
Humidity
70%
Dew point
57°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 186°F62°F101°F 202650°F 200924%0%
Sep 286°F61°F101°F 202650°F 200924%0%
Sep 386°F61°F101°F 201152°F 202524%0%
Sep 486°F61°F102°F 202648°F 199724%0%
Sep 586°F60°F104°F 202645°F 199724%0%
Sep 685°F60°F96°F 199848°F 201724%0%
Sep 785°F60°F96°F 200245°F 201724%0%
Sep 885°F59°F96°F 200243°F 202524%0%
Sep 985°F59°F98°F 200241°F 202424%0%
Sep 1084°F59°F97°F 200246°F 199824%0%
Sep 1184°F58°F96°F 201348°F 199824%0%
Sep 1284°F58°F93°F 201949°F 199724%0%
Sep 1383°F58°F93°F 201146°F 201424%0%
Sep 1483°F57°F94°F 202544°F 199924%0%
Sep 1583°F57°F97°F 202643°F 200724%0%
Sep 1682°F57°F95°F 202643°F 200024%0%
Sep 1782°F56°F97°F 202644°F 201424%0%
Sep 1882°F56°F95°F 201844°F 201224%0%
Sep 1981°F55°F95°F 201840°F 201225%0%
Sep 2081°F55°F95°F 201843°F 200325%0%
Sep 2181°F54°F98°F 201045°F 200625%0%
Sep 2280°F54°F95°F 200538°F 199925%0%
Sep 2380°F54°F96°F 201036°F 201225%0%
Sep 2480°F53°F94°F 200734°F 201225%0%
Sep 2579°F53°F93°F 201739°F 200125%0%
Sep 2679°F52°F93°F 201736°F 200125%0%
Sep 2779°F52°F92°F 199842°F 200025%0%
Sep 2878°F52°F93°F 199939°F 202225%0%
Sep 2978°F51°F94°F 201941°F 202225%0%
Sep 3077°F51°F95°F 201939°F 200426%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Knox County, in percent, and of at least 0.1 inch of snowfall.01020301102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (EDT).

September 1
sunrise 7:19 AM, sunset 8:20 PM
September 30
sunrise 7:45 AM, sunset 7:34 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00129113 (Vincennes 5 Ne), public domain. Records: NOAA GHCN-Daily, station USW00013809, 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.