Tri-Cities climate — normals and trends
Tri-Cities (United States) has a cold semi-arid climate (BSk) under the Köppen-Geiger classification. Its mean annual temperature is 12.9 °C and it receives 242 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (26.0 °C on average) and the coldest is January (0.5 °C). Rainfall peaks in December.
Tri-Cities averages 74 frost days, 74 hot days (≥ 30 °C) and 61 rainy days per year.
Tri-Cities has warmed by +1.7 °C between 1940 and 2025, or +0.20 °C per decade. This trend is statistically significant.
The number of frost days there went from about 83 to 65 per year over the period.
The hottest day of the period reached 47.9 °C (on 29 June 2021) and the coldest -31.8 °C (on 2 February 1950).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
Tri-CitiesWashington
- coords
- 46.25°, -119.20°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
12.9°C
Average daily high
18.9°C
Average daily low
7.0°C
Annual rainfall
242mm
Sunshine / day
10.1h
Mean relative humidity
56%
Average peak wind
15.3km/h
Seasonal range
25.5°C
Frost days (< 0 °C)
74 d/yr
Hot days (≥ 30 °C)
74 d/yr
Rainy days (≥ 1 mm)
61 d/yr
Annual snowfall
18.8 cm
Average feels-like high
16.0 °C
Average feels-like low
4.3 °C
Average peak gust
32.5 km/h
Tropical nights (≥ 20 °C)
15 d/yr
Solar radiation
16.2 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.32 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
47.9 °C
29 June 2021
Coldest day
-31.8 °C
2 February 1950
Wettest day
31 mm
21 December 1964
Windiest day
57.0 km/h
8 January 1990
Strongest gust
107.6 km/h
8 January 1990
Hottest feels-like
48.4 °C
29 June 2021
Coldest feels-like
-36.4 °C
2 February 1950
Snowiest day
10.6 cm
19 November 1996
Sunniest day
15.6 h
13 June 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 4.8 °C | +0.6 °C | 31 mm | -4 mm |
| Feb | 7.2 °C | -1.5 °C | 36 mm | +11 mm |
| Mar | 15.7 °C | +1.7 °C | 25 mm | +2 mm |
| Apr | 21.6 °C | +2.2 °C | 13 mm | -7 mm |
| May | 26.2 °C | +1.4 °C | 4 mm | -15 mm |
| Jun | 31.7 °C | +2.8 °C | 1 mm | -12 mm |
| Jul | 35.3 °C | +1.6 °C | 3 mm | -2 mm |
| Aug | 33.9 °C | +1.5 °C | 3 mm | -3 mm |
| Sep | 30.0 °C | +3.0 °C | 4 mm | -6 mm |
| Oct | 17.9 °C | -0.8 °C | 23 mm | +2 mm |
| Nov | 11.2 °C | +1.5 °C | 36 mm | +3 mm |
| Dec | 9.7 °C | +4.9 °C | 50 mm | +15 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Tri-Cities?
Tri-Cities has a cold semi-arid climate (Köppen BSk). Over 1940-2025, the average annual temperature is 12.9 °C and it receives 242 mm of precipitation per year.
What is the hottest day ever recorded in Tri-Cities?
The hottest day measured in Tri-Cities between 1940 and 2025 was 29 June 2021, reaching 47.9 °C.
What is the coldest day in Tri-Cities?
The coldest day measured in Tri-Cities between 1940 and 2025 was 2 February 1950, at -31.8 °C.
Does it snow in Tri-Cities?
Yes. Tri-Cities gets on average 18.8 cm of snow per year and has around 74 frost days.
Has the climate of Tri-Cities warmed?
Yes: Tri-Cities warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Tri-Cities?
The wettest day measured in Tri-Cities between 1940 and 2025 was 21 December 1964, with 31 mm of rain in 24 hours.
What was the windiest day in Tri-Cities?
The windiest day measured in Tri-Cities between 1940 and 2025 was 8 January 1990, with winds reaching 57.0 km/h.
What is the warmest month in Tri-Cities?
The warmest month in Tri-Cities is July (26.0 °C on average); the coldest is January (0.5 °C).
How much does it rain in Tri-Cities?
Tri-Cities receives on average 242 mm of precipitation per year, spread over about 61 rainy days.
Is it sunny in Tri-Cities?
Tri-Cities gets on average 10.1 hours of sunshine per day, roughly 3,687 hours per year over 1940-2025.
What is the biggest single-day snowfall in Tri-Cities?
The heaviest 24-hour snowfall measured in Tri-Cities between 1940 and 2025 was 19 November 1996, with 10.6 cm.
Are there tropical nights in Tri-Cities?
Yes: Tri-Cities has on average 15 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Tri-Cities?
In Tri-Cities, between 1940 and 2025, the highest apparent temperature reached 48.4 °C on 29 June 2021, and the lowest was -36.4 °C on 2 February 1950.
Compare Tri-Cities with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Tri-Cities