Tri-City climate

Tri-City Weather in September

NOAA 1991-2020 normals for Riddle, 5.3 km from Tri-City

Average highs run from 87°F on September 1 to 79°F on September 30, and lows from 51°F to 46°F. Normal precipitation for the month is 0.71 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 Tri-City, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
84°F
Average low
49°F
Precipitation
0.71 in
Record high
105°FSep 5, 2024
Record low
32°FSep 30, 1954
Chance of a freeze
0%
Days of 90°F or more
6.8
Daylight
13 h 10 min to 11 h 46 min
Cloud cover
43%
Humidity
65%
Dew point
46°F
Wind
4.0 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 187°F51°F99°F 199844°F 195511%0%
Sep 287°F51°F104°F 193446°F 193311%0%
Sep 387°F51°F99°F 202041°F 195812%0%
Sep 487°F51°F102°F 195541°F 195812%0%
Sep 586°F51°F105°F 202441°F 195412%0%
Sep 686°F51°F99°F 195842°F 194713%0%
Sep 786°F50°F98°F 193542°F 193913%0%
Sep 886°F50°F100°F 193542°F 196214%0%
Sep 986°F50°F98°F 194440°F 196414%0%
Sep 1085°F50°F99°F 194441°F 193115%0%
Sep 1185°F50°F99°F 200943°F 193115%0%
Sep 1285°F49°F98°F 194842°F 196216%0%
Sep 1385°F49°F97°F 201242°F 195216%0%
Sep 1484°F49°F101°F 193742°F 195217%0%
Sep 1584°F49°F97°F 202343°F 193617%0%
Sep 1684°F48°F96°F 202539°F 193618%0%
Sep 1784°F48°F99°F 196233°F 196518%0%
Sep 1883°F48°F91°F 195234°F 196519%0%
Sep 1983°F48°F95°F 193934°F 196520%0%
Sep 2083°F48°F98°F 201438°F 195820%0%
Sep 2182°F47°F98°F 193934°F 195521%0%
Sep 2282°F47°F101°F 200936°F 195521%0%
Sep 2382°F47°F100°F 194337°F 196122%0%
Sep 2481°F47°F99°F 202437°F 195822%0%
Sep 2581°F47°F91°F 195236°F 195523%0%
Sep 2681°F46°F95°F 201635°F 193423%0%
Sep 2780°F46°F98°F 200336°F 196124%0%
Sep 2880°F46°F95°F 193536°F 195425%0%
Sep 2979°F46°F96°F 202035°F 195425%0%
Sep 3079°F46°F90°F 193532°F 195426%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Tri-City, 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 (PDT).

September 1
sunrise 6:38 AM, sunset 7:48 PM
September 30
sunrise 7:10 AM, sunset 6:56 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00357169 (Riddle), public domain. Records: NOAA GHCN-Daily, station USW00024231, 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.