Prince William County climate

Prince William County Weather in September

NOAA 1991-2020 normals for Manassas, 3.7 km from Prince William County

Average highs run from 83°F on September 1 to 73°F on September 30, and lows from 63°F to 53°F.

September day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Prince William County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
78°F
Average low
58°F
Record high
100°FSep 6, 2023
Record low
30°FSep 24, 1974
Chance of a freeze
0%
Days of 90°F or more
3.3
Daylight
13 h 01 min to 11 h 49 min
Cloud cover
54%
Humidity
72%
Dew point
58°F
Wind
4.7 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 183°F63°F98°F 196249°F 19700%
Sep 282°F63°F99°F 198044°F 19700%
Sep 382°F63°F99°F 202345°F 19670%
Sep 482°F62°F99°F 202348°F 19970%
Sep 582°F62°F99°F 202342°F 19970%
Sep 681°F62°F100°F 202345°F 19720%
Sep 781°F62°F97°F 202341°F 19760%
Sep 881°F61°F96°F 201643°F 19840%
Sep 981°F61°F98°F 201640°F 19860%
Sep 1080°F61°F99°F 198343°F 19810%
Sep 1180°F60°F99°F 198340°F 19760%
Sep 1280°F60°F95°F 199840°F 19670%
Sep 1379°F59°F94°F 197443°F 19850%
Sep 1479°F59°F95°F 199837°F 19850%
Sep 1579°F59°F95°F 199338°F 19850%
Sep 1678°F58°F97°F 199137°F 19840%
Sep 1778°F58°F97°F 199135°F 19860%
Sep 1878°F58°F91°F 197837°F 19900%
Sep 1977°F57°F93°F 197736°F 19840%
Sep 2077°F57°F91°F 196540°F 19790%
Sep 2177°F56°F92°F 196533°F 19620%
Sep 2276°F56°F94°F 197035°F 19620%
Sep 2376°F56°F94°F 201933°F 19830%
Sep 2475°F55°F97°F 201030°F 19740%
Sep 2575°F55°F93°F 201033°F 19830%
Sep 2675°F54°F93°F 200738°F 19640%
Sep 2774°F54°F96°F 199835°F 19840%
Sep 2874°F54°F86°F 199834°F 19890%
Sep 2974°F53°F89°F 201934°F 19780%
Sep 3073°F53°F92°F 198635°F 19930%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Prince William County, in percent, and of at least 0.1 inch of snowfall.00.21102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (EDT).

September 1
sunrise 6:39 AM, sunset 7:40 PM
September 30
sunrise 7:05 AM, sunset 6:54 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00445204 (Manassas), public domain. Records: NOAA GHCN-Daily, station USW00093738, 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.