Benton County climate

Benton County Weather in September

NOAA 1991-2020 normals for Prosser, 19.5 km from Benton County

Average highs run from 85°F on September 1 to 74°F on September 30, and lows from 54°F to 46°F. Normal precipitation for the month is 0.27 in over about 3 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 Benton County, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
80°F
Average low
50°F
Precipitation
0.27 in
Record high
106°FSep 3, 1950
Record low
31°FSep 25, 1972
Chance of a freeze
3%
Days of 90°F or more
3.8
Daylight
13 h 17 min to 11 h 44 min
Cloud cover
40%
Humidity
47%
Dew point
43°F
Wind
7.6 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation.

DateNormal highNormal lowRecord highRecord lowChance wet
Sep 185°F54°F102°F 202044°F 19737%
Sep 285°F54°F104°F 195044°F 19997%
Sep 384°F53°F106°F 195045°F 19588%
Sep 484°F53°F101°F 195543°F 19698%
Sep 584°F53°F99°F 195543°F 19568%
Sep 683°F53°F103°F 202042°F 19698%
Sep 783°F52°F102°F 194443°F 19608%
Sep 883°F52°F100°F 195840°F 19768%
Sep 982°F52°F97°F 194440°F 19629%
Sep 1082°F52°F97°F 194440°F 19709%
Sep 1182°F51°F99°F 194442°F 19889%
Sep 1281°F51°F98°F 197340°F 20129%
Sep 1381°F51°F97°F 194840°F 19499%
Sep 1481°F51°F100°F 194838°F 19709%
Sep 1580°F50°F95°F 195735°F 197010%
Sep 1680°F50°F96°F 195337°F 197010%
Sep 1779°F50°F95°F 196732°F 196510%
Sep 1879°F50°F95°F 195237°F 194410%
Sep 1979°F49°F96°F 195137°F 198310%
Sep 2078°F49°F94°F 195233°F 198310%
Sep 2178°F49°F95°F 195237°F 197111%
Sep 2277°F49°F98°F 196736°F 199311%
Sep 2377°F48°F93°F 195032°F 200011%
Sep 2476°F48°F94°F 195232°F 200011%
Sep 2576°F48°F96°F 195231°F 197211%
Sep 2676°F47°F99°F 195231°F 197211%
Sep 2775°F47°F96°F 195231°F 197212%
Sep 2875°F47°F92°F 194931°F 197212%
Sep 2974°F47°F91°F 196331°F 198312%
Sep 3074°F46°F91°F 197631°F 198412%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Benton County, in percent.02.557.51012.51102030
  • Chance of a wet day

Sunrise and sunset

Times for 2026, local time (PDT).

September 1
sunrise 6:19 AM, sunset 7:36 PM
September 30
sunrise 6:56 AM, sunset 6:40 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00456768 (Prosser), public domain. Records: NOAA GHCN-Daily, station USC00457015, 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.