Boone County climate

Boone County Weather in September

NOAA 1991-2020 normals for Marengo, 18.9 km from Boone County

Average highs run from 80°F on September 1 to 70°F on September 30, and lows from 57°F to 46°F. Normal precipitation for the month is 3.68 in over about 7 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 Boone County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
75°F
Average low
52°F
Precipitation
3.68 in
Record high
102°FSep 1, 1953
Record low
27°FSep 30, 1984
Chance of a freeze
15%
Days of 90°F or more
1.5
Daylight
13 h 08 min to 11 h 47 min
Cloud cover
51%
Humidity
75%
Dew point
54°F
Wind
9.2 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°F57°F102°F 195342°F 196726%0%
Sep 280°F57°F101°F 195342°F 196726%0%
Sep 379°F57°F96°F 201245°F 197426%0%
Sep 479°F56°F96°F 201239°F 197426%0%
Sep 579°F56°F95°F 195444°F 196226%0%
Sep 679°F56°F96°F 195439°F 198825%0%
Sep 778°F55°F95°F 195937°F 198625%0%
Sep 878°F55°F95°F 197837°F 198625%0%
Sep 978°F55°F97°F 195542°F 197525%0%
Sep 1078°F54°F96°F 201341°F 197625%0%
Sep 1177°F54°F91°F 195240°F 199325%0%
Sep 1277°F54°F91°F 195236°F 197525%0%
Sep 1377°F53°F92°F 200532°F 197525%0%
Sep 1476°F53°F92°F 197135°F 197525%0%
Sep 1576°F52°F89°F 195535°F 200725%0%
Sep 1676°F52°F89°F 195535°F 198425%0%
Sep 1775°F51°F93°F 198838°F 199925%0%
Sep 1875°F51°F91°F 195535°F 195925%0%
Sep 1974°F51°F93°F 202138°F 201225%0%
Sep 2074°F50°F91°F 201730°F 195625%0%
Sep 2174°F50°F92°F 201034°F 199525%0%
Sep 2273°F49°F92°F 201730°F 197625%0%
Sep 2373°F49°F93°F 201729°F 197424%0%
Sep 2473°F48°F92°F 200728°F 197624%0%
Sep 2572°F48°F92°F 201735°F 198924%0%
Sep 2672°F47°F90°F 199832°F 197524%0%
Sep 2771°F47°F90°F 202130°F 199124%0%
Sep 2871°F46°F91°F 195232°F 199124%0%
Sep 2970°F46°F94°F 195329°F 198424%0%
Sep 3070°F46°F92°F 197127°F 198424%0%

Chance of rain

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

September 1
sunrise 6:21 AM, sunset 7:29 PM
September 30
sunrise 6:51 AM, sunset 6:38 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00115326 (Marengo), public domain. Records: NOAA GHCN-Daily, station USW00094822, 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.