O'Brien, OR climate
O'Brien has mild winters and warm summers, with plenty of rain. A typical July afternoon reaches 89°, a January night drops to 33°, and about 7 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in O'Brien feels like
Winter
Spring
Summer
Fall
O'Brien 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 | 49° | 33° | 11.2" | 2.1" | 17 | 2 | 36° – 47° |
| February | 53° | 33° | 8.5" | 1.2" | 14 | 1 | 36° – 49° |
| March | 58° | 34° | 8.2" | 1.5" | 16 | 0 | 41° – 51° |
| April | 63° | 37° | 4.7" | 0.2" | 13 | 0 | 46° – 54° |
| May | 72° | 42° | 2.3" | 0 | 8 | 0 | 51° – 64° |
| June | 80° | 47° | 1.0" | 0 | 4 | 0 | 59° – 70° |
| July | 89° | 52° | 0.2" | 0 | 1 | 0 | 64° – 74° |
| August | 89° | 50° | 0.3" | 0 | 1 | 0 | 66° – 74° |
| September | 83° | 45° | 0.9" | 0 | 3 | 0 | 60° – 68° |
| October | 69° | 39° | 3.7" | 0 | 7 | 0 | 51° – 59° |
| November | 54° | 36° | 8.5" | 0.2" | 16 | 0 | 38° – 50° |
| December | 47° | 33° | 13.5" | 1.9" | 19 | 0 | 36° – 44° |
| Year | 67° | 40° | 63.0" | 7.1" | 119 | 3 |
“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 O'Brien
O'Brien gets 63 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 119 days a year.
About 161 frost-free days a year
In half of years the last 32° night comes by May 1 and the first one by October 12. That leaves about 161 frost-free days for gardens, shorter than 70% of U.S. towns.
Heating and cooling a home in O'Brien
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In O'Brien, 87% of that work is heating and 13% 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 O'Brien 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 O'Brien averaged 1.6° warmer than the 1900s. The biggest change is in January (+2.8°). The shift is larger than in 78% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at O'Brien’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. May swings the most: between 1991 and 2020 its average temperature ranged from 51° to 64°. December is the most reliable, staying within 7°.
Common questions about O'Brien’s climate
What is the coldest month in O'Brien?
December, with a typical high of 47° and a low of 33°.
What is the hottest month in O'Brien?
July, with a typical high of 89° and a low of 52°. About 73 days a year reach 90°.
How much snow does O'Brien get?
About 7 inches in a normal winter, most of it in January.
When is the first frost in O'Brien?
In half of years the first 32° night comes by October 12, and the last spring frost by May 1.
What is the rainiest month in O'Brien?
December, with 13.5 inches of rain and melted snow. The year totals 63 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for O'Brien itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Cave Junction 1 Wnw, OR (6 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.