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Tri-Cities, Washington climate
BSk Cold semi-arid
Tri-Cities has a seasonal mild-temperate climate (Cold semi-arid, Köppen BSk). The hottest month is July with an average daily high near 33°C, while the coldest is January averaging around −2°C at night. Precipitation totals about 200 mm a year and is strongly seasonal — January alone averages 29 mm while August barely receives 4 mm.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsTri-Cities climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 5 | 9 | 15 | 19 | 24 | 28 | 33 | 32 | 27 | 19 | 11 | 5 |
| Avg temp (°C) | 2 | 4 | 8 | 12 | 17 | 21 | 25 | 24 | 19 | 13 | 6 | 2 |
| Avg low (°C) | −2 | −1 | 2 | 6 | 10 | 14 | 17 | 16 | 12 | 6 | 2 | −1 |
| Precipitation (mm) | 29 | 20 | 17 | 15 | 21 | 15 | 5 | 4 | 7 | 17 | 22 | 27 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 5 | 9 | 15 | 19 | 24 | 28 |
| Avg temp (°C) | 2 | 4 | 8 | 12 | 17 | 21 |
| Avg low (°C) | −2 | −1 | 2 | 6 | 10 | 14 |
| Precipitation (mm) | 29 | 20 | 17 | 15 | 21 | 15 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 33 | 32 | 27 | 19 | 11 | 5 |
| Avg temp (°C) | 25 | 24 | 19 | 13 | 6 | 2 |
| Avg low (°C) | 17 | 16 | 12 | 6 | 2 | −1 |
| Precipitation (mm) | 5 | 4 | 7 | 17 | 22 | 27 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 8 | 8 | 7 | 6 | 4 | 2 | 2 | 3 | 6 | 9 | 10 |
| Days with high ≥ 32°C (days) | — | — | — | — | 2 | 5 | 19 | 17 | 4 | — | — | — |
| Days with low ≤ 0°C (days) | 18 | 16 | 8 | 1 | — | — | — | — | — | 2 | 11 | 19 |
| Days with snowfall ≥ 2.5 cm (days) | 0.6 | 0.4 | 0.1 | — | — | — | — | — | — | — | 0.1 | 0.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 8 | 8 | 7 | 6 | 4 |
| Days with high ≥ 32°C (days) | — | — | — | — | 2 | 5 |
| Days with low ≤ 0°C (days) | 18 | 16 | 8 | 1 | — | — |
| Days with snowfall ≥ 2.5 cm (days) | 0.6 | 0.4 | 0.1 | — | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 2 | 2 | 3 | 6 | 9 | 10 |
| Days with high ≥ 32°C (days) | 19 | 17 | 4 | — | — | — |
| Days with low ≤ 0°C (days) | — | — | — | 2 | 11 | 19 |
| Days with snowfall ≥ 2.5 cm (days) | — | — | — | — | 0.1 | 0.5 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 75 | 68 | 67 | 62 | 58 | 50 | 30 | 31 | 40 | 56 | 70 | 74 |
| Clear days (≤ 30% cloud) | 2 | 4 | 4 | 5 | 7 | 9 | 19 | 18 | 14 | 8 | 3 | 2 |
| Partly cloudy days (30–70%) | 9 | 8 | 10 | 11 | 10 | 11 | 8 | 9 | 9 | 10 | 10 | 9 |
| Cloudy days (≥ 70%) | 21 | 16 | 17 | 14 | 13 | 9 | 4 | 4 | 7 | 12 | 17 | 20 |
| Relative humidity (%) | 81 | 73 | 64 | 58 | 53 | 49 | 43 | 42 | 47 | 60 | 73 | 79 |
| Wind speed (mph) | 5.5 | 5.7 | 5.9 | 6.1 | 6.0 | 6.4 | 6.0 | 5.6 | 5.1 | 5.3 | 5.5 | 5.5 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 75 | 68 | 67 | 62 | 58 | 50 |
| Clear days (≤ 30% cloud) | 2 | 4 | 4 | 5 | 7 | 9 |
| Partly cloudy days (30–70%) | 9 | 8 | 10 | 11 | 10 | 11 |
| Cloudy days (≥ 70%) | 21 | 16 | 17 | 14 | 13 | 9 |
| Relative humidity (%) | 81 | 73 | 64 | 58 | 53 | 49 |
| Wind speed (mph) | 5.5 | 5.7 | 5.9 | 6.1 | 6.0 | 6.4 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 30 | 31 | 40 | 56 | 70 | 74 |
| Clear days (≤ 30% cloud) | 19 | 18 | 14 | 8 | 3 | 2 |
| Partly cloudy days (30–70%) | 8 | 9 | 9 | 10 | 10 | 9 |
| Cloudy days (≥ 70%) | 4 | 4 | 7 | 12 | 17 | 20 |
| Relative humidity (%) | 43 | 42 | 47 | 60 | 73 | 79 |
| Wind speed (mph) | 6.0 | 5.6 | 5.1 | 5.3 | 5.5 | 5.5 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Kennewick (NOAA GHCN station USC00454154), about 8 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.