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Tri-Cities, WA Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Tri-Cities, WA?
Tri-Cities, WA gets 7.6 in of precipitation a year over about 77 rainy days. July is the warmest month (average high 93°F) and December the coldest (average low 27°F).
Semi-arid climate
Tri-Cities, WA has hot summers and chilly winters. Daytime highs range from about 41°F in December to 93°F in July. January is usually the wettest month. The most comfortable time to visit is typically April to May and October, when daytime highs sit near 70°F.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 28° | 44° |
| Spring | Mar–May | 39° | 68° |
| Summer | Jun–Aug | 55° | 89° |
| Autumn | Sep–Nov | 39° | 66° |
How much rain does Tri-Cities get?
Tri-Cities gets 7.6 in of precipitation in an average year, spread over about 77 days with measurable rain. That is fewer rainy days than 61% of the US.
January is the wettest month, with 1.0 in. July is the driest, with 0.1 in. December has the most rainy days, about 10.
The longest dry spell in the last five years lasted 88 days, to August 15, 2025.
From September 2025 to August 2026 Tri-Cities got 8.9 in of rain, against a normal of 7.6 in for those months. February 2026 had the most, with 2.3 in.
See where Tri-Cities ranks: rainiest cities in the US, US cities with the most rainy days, rainiest cities in Washington.
Tri-Cities weather by month
Tri-Cities weather in January
In January, Tri-Cities averages a high of 42°F and a low of 28°F. It gets 1.0 in of precipitation over about 10 rainy days. Estimated sunshine is 25% of daylight hours, derived from ERA5 cloud cover. The January record high is 67°F (2002) and the record low is -19°F (2004).
Tri-Cities weather in February
In February, Tri-Cities averages a high of 49°F and a low of 29°F. It gets 0.6 in of precipitation over about 8 rainy days. Estimated sunshine is 42% of daylight hours, derived from ERA5 cloud cover. The February record high is 69°F (2022) and the record low is -2°F (2019).
Tri-Cities weather in March
In March, Tri-Cities averages a high of 59°F and a low of 33°F. It gets 0.7 in of precipitation over about 8 rainy days. Estimated sunshine is 44% of daylight hours, derived from ERA5 cloud cover. The March record high is 80°F (2024) and the record low is -1°F (2019).
Tri-Cities weather in April
In April, Tri-Cities averages a high of 67°F and a low of 39°F. It gets 0.7 in of precipitation over about 7 rainy days. Estimated sunshine is 48% of daylight hours, derived from ERA5 cloud cover. The April record high is 94°F (1998) and the record low is 21°F (2008). April is one of the most comfortable months to visit.
Tri-Cities weather in May
In May, Tri-Cities averages a high of 76°F and a low of 46°F. It gets 0.7 in of precipitation over about 7 rainy days. Estimated sunshine is 51% of daylight hours, derived from ERA5 cloud cover. The May record high is 101°F (2001) and the record low is 28°F (2013). May is one of the most comfortable months to visit.
Tri-Cities weather in June
In June, Tri-Cities averages a high of 84°F and a low of 53°F. It gets 0.6 in of precipitation over about 5 rainy days. Estimated sunshine is 58% of daylight hours, derived from ERA5 cloud cover. The June record high is 115°F (2021) and the record low is 37°F (2002).
Tri-Cities weather in July
In July, Tri-Cities averages a high of 93°F and a low of 57°F. It gets 0.1 in of precipitation over about 2 rainy days. Estimated sunshine is 87% of daylight hours, derived from ERA5 cloud cover. The July record high is 112°F (2006) and the record low is 42°F (1999).
Tri-Cities weather in August
In August, Tri-Cities averages a high of 91°F and a low of 56°F. It gets 0.3 in of precipitation over about 2 rainy days. Estimated sunshine is 73% of daylight hours, derived from ERA5 cloud cover. The August record high is 111°F (1998) and the record low is 40°F (2008).
Tri-Cities weather in September
In September, Tri-Cities averages a high of 81°F and a low of 48°F. It gets 0.3 in of precipitation over about 3 rainy days. Estimated sunshine is 65% of daylight hours, derived from ERA5 cloud cover. The September record high is 102°F (2022) and the record low is 26°F (2000).
Tri-Cities weather in October
In October, Tri-Cities averages a high of 66°F and a low of 39°F. It gets 0.7 in of precipitation over about 6 rainy days. Estimated sunshine is 58% of daylight hours, derived from ERA5 cloud cover. The October record high is 90°F (2020) and the record low is 9°F (2002). October is one of the most comfortable months to visit.
Tri-Cities weather in November
In November, Tri-Cities averages a high of 51°F and a low of 32°F. It gets 0.9 in of precipitation over about 9 rainy days. Estimated sunshine is 34% of daylight hours, derived from ERA5 cloud cover. The November record high is 77°F (1999) and the record low is -7°F (2010).
Tri-Cities weather in December
In December, Tri-Cities averages a high of 41°F and a low of 27°F. It gets 1.0 in of precipitation over about 10 rainy days. Estimated sunshine is 23% of daylight hours, derived from ERA5 cloud cover. The December record high is 71°F (2021) and the record low is -9°F (2016).
Sunshine, humidity and wind in Tri-Cities
July is the sunniest month in Tri-Cities, with estimated sunshine of 87% of daylight hours from ERA5 cloud cover. December is the cloudiest, at 23%. The annual cloud-cover estimate is 51% of daylight hours; it is not a measurement of sunshine duration. Tri-Cities is sunnier than 64% of the US.
Humidity peaks in December at 79% and is lowest in July at 24%.
Wind averages 6 mph over the year, and April is the windiest month at 8 mph.
Tri-Cities has about 57 days a year above 90°F. Tri-Cities is hotter than 73% of the US.
Thunderstorms occur on about 6 days a year.
See where Tri-Cities ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.
First and last freeze in Tri-Cities
The first fall freeze in Tri-Cities typically comes around October 13, and the last spring freeze around April 30. That leaves a frost-free growing season of about 166 days.
Tri-Cities weather records
These records cover PASCO TRI CITIES AP during 1998–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Tri-Cities station is 115°F, on June 27, 2021. The coldest is -19°F, on January 4, 2004.
The wettest day in the available station history brought 1.1 in of precipitation, on June 1, 2011.
The best time to visit Tri-Cities
The most comfortable time to visit is typically April to May and October, when daytime highs sit near 70°F.
Winter (December–February) is chilly, with average highs around 44°F and lows near 28°F.
Spring (March–May) is mild, with average highs around 68°F and lows near 39°F.
Summer (June–August) is hot, with average highs around 89°F and lows near 55°F.
Autumn (September–November) is mild, with average highs around 66°F and lows near 39°F.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Wind | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|---|
| January | 28° | 42° | 1.0 in | 10 | 6 mph | 77% | 25% | 67° | -19° |
| February | 29° | 49° | 0.63 in | 8 | 6 mph | 64% | 42% | 69° | -2° |
| March | 33° | 59° | 0.69 in | 8 | 8 mph | 50% | 44% | 80° | -1° |
| April | 39° | 67° | 0.66 in | 7 | 8 mph | 34% | 48% | 94° | 21° |
| May | 46° | 76° | 0.71 in | 7 | 7 mph | 34% | 51% | 101° | 28° |
| June | 53° | 84° | 0.61 in | 5 | 8 mph | 29% | 58% | 115° | 37° |
| July | 57° | 93° | 0.15 in | 2 | 6 mph | 24% | 87% | 112° | 42° |
| August | 56° | 91° | 0.27 in | 2 | 6 mph | 29% | 73% | 111° | 40° |
| September | 48° | 81° | 0.31 in | 3 | 5 mph | 38% | 65% | 102° | 26° |
| October | 39° | 66° | 0.66 in | 6 | 6 mph | 55% | 58% | 90° | 9° |
| November | 32° | 51° | 0.87 in | 9 | 6 mph | 74% | 34% | 77° | -7° |
| December | 27° | 41° | 1.0 in | 10 | 6 mph | 79% | 23% | 71° | -9° |
Station: PASCO TRI CITIES AP, 7 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1998–2026; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Tri-Cities climate questions
How much rain does Tri-Cities get?
Tri-Cities gets 7.6 in of precipitation in an average year, over about 77 rainy days.
What is the wettest month in Tri-Cities?
January is the wettest month in Tri-Cities, with 1.0 in. July is the driest, with 0.1 in.
How many rainy days does Tri-Cities have a year?
Tri-Cities has about 77 days with measurable rain in an average year. December has the most, about 10.
What is the hottest month in Tri-Cities?
July is the warmest month in Tri-Cities, with an average high of 93°F.
What is the coldest month in Tri-Cities?
December is the coldest month in Tri-Cities, with an average low of 27°F.
What is the record high temperature in Tri-Cities?
Within the available 1998–2026 station history, the record high at the Tri-Cities station is 115°F, set on June 27, 2021. The record low is -19°F, on January 4, 2004.
What is the sunniest month in Tri-Cities?
July is the sunniest month in Tri-Cities, with estimated sunshine of 87% of daylight hours from ERA5 cloud cover. December is the cloudiest.
When is the first frost in Tri-Cities?
The first fall freeze in Tri-Cities typically comes around October 13. The last spring freeze is around April 30.
What is the best time to visit Tri-Cities?
The most comfortable time to visit is typically April to May and October, when daytime highs sit near 70°F.