Tri-City, OR climate
Tri-City has mild winters and warm summers. A typical July afternoon reaches 87°, a January night drops to 36°, and about 2 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Tri-City feels like
Winter
Spring
Summer
Fall
Tri-City weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 50° | 36° | 4.9" | 0.5" | 19 | 0 | 38° – 48° |
| February | 54° | 37° | 3.7" | 0.7" | 17 | 0 | 39° – 50° |
| March | 59° | 38° | 3.7" | 0.1" | 18 | 0 | 44° – 54° |
| April | 64° | 40° | 2.8" | 0 | 16 | 0 | 48° – 58° |
| May | 72° | 46° | 2.0" | 0 | 12 | 0 | 54° – 65° |
| June | 78° | 50° | 1.0" | 0 | 6 | 0 | 60° – 71° |
| July | 87° | 55° | 0.3" | 0 | 2 | 0 | 64° – 75° |
| August | 87° | 54° | 0.3" | 0 | 2 | 0 | 66° – 75° |
| September | 81° | 49° | 0.8" | 0 | 5 | 0 | 62° – 68° |
| October | 68° | 43° | 2.4" | 0 | 12 | 0 | 52° – 61° |
| November | 55° | 40° | 4.8" | 0 | 19 | 0 | 41° – 51° |
| December | 47° | 36° | 6.2" | 0.6" | 20 | 0 | 37° – 46° |
| Year | 67° | 43° | 32.8" | 1.9" | 147 | 1 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Tri-City
Tri-City gets 33 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 147 days a year.
About 221 frost-free days a year
In half of years the last 32° night comes by March 31 and the first one by November 6. That leaves about 221 frost-free days for gardens, longer than 82% of U.S. towns.
Heating and cooling a home in Tri-City
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Tri-City, 85% of that work is heating and 15% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Tri-City compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Tri-City averaged 1.7° warmer than the 1900s. The biggest change is in January (+2.8°). The shift is larger than in 84% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Tri-City’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 39° to 50°. September is the most reliable, staying within 7°.
Common questions about Tri-City’s climate
What is the coldest month in Tri-City?
December, with a typical high of 47° and a low of 36°.
What is the hottest month in Tri-City?
August, with a typical high of 87° and a low of 54°. About 35 days a year reach 90°.
How much snow does Tri-City get?
About 2 inches in a normal winter, most of it in February.
When is the first frost in Tri-City?
In half of years the first 32° night comes by November 6, and the last spring frost by March 31.
What is the rainiest month in Tri-City?
December, with 6.2 inches of rain and melted snow. The year totals 33 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Tri-City itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Riddle, OR (4 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.