Weather in Tri-Cities, Washington, United States in September
In an average September, Tri-Cities sees a daily high around 78°F and a low around 54°F, based on 1981–2026 of local climate records.
| Average high | 78°F |
|---|---|
| Typical high range | 68°F to 89°F |
| Average low | 54°F |
| Typical low range | 47°F to 60°F |
| Average daily precipitation | 0.00 in |
September records
The most extreme September on record for each metric, across 1981–2026. For rainfall, the wettest and driest are by total September accumulation.
High
Highest
101°F
1987-09-01
Lowest
51°F
2019-09-29
Low
Highest
71°F
2003-09-04
Lowest
33°F
1985-09-29
Feels-like
Highest
107°F
2025-09-02
Lowest
25°F
1984-09-24
Humidity
Highest
13.9 g/m³
2013-09-05
Lowest
3.2 g/m³
1999-09-28
Wind
Highest
29 mph
2020-09-07
Lowest
5 mph
1987-09-27
Precip
Wettest
2.00 in
2013
Driest
0.01 in
1999
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