Harper, OR climate
Harper has chilly winters and hot summers, with very little rain. A typical July afternoon reaches 94°, a January night drops to 20°, and about 6 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Harper feels like
Winter
Spring
Summer
Fall
Harper 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 | 39° | 20° | 1.1" | 2.1" | 9 | 5 | 20° – 35° |
| February | 47° | 24° | 0.7" | 0.6" | 7 | 2 | 27° – 42° |
| March | 58° | 30° | 0.8" | 0.1" | 8 | 0 | 39° – 50° |
| April | 66° | 34° | 0.7" | 0 | 8 | 0 | 45° – 56° |
| May | 75° | 43° | 0.9" | 0 | 9 | 0 | 52° – 66° |
| June | 83° | 49° | 0.7" | 0 | 5 | 0 | 61° – 75° |
| July | 94° | 56° | 0.3" | 0 | 3 | 0 | 63° – 80° |
| August | 92° | 53° | 0.2" | 0 | 2 | 0 | 66° – 76° |
| September | 82° | 44° | 0.4" | 0 | 3 | 0 | 59° – 67° |
| October | 67° | 33° | 0.6" | 0 | 5 | 0 | 42° – 57° |
| November | 50° | 25° | 0.7" | 0.1" | 8 | 0 | 31° – 43° |
| December | 39° | 20° | 1.1" | 3.1" | 10 | 4 | 23° – 34° |
| Year | 66° | 36° | 8.2" | 6.0" | 77 | 12 |
“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 Harper
Harper gets 8 inches of rain and melted snow a year. December is the wettest month and August the driest. Rain or snow falls on about 77 days a year. Snow covers the ground about 12 days of the year.
About 147 frost-free days a year
In half of years the last 32° night comes by May 7 and the first one by October 3. That leaves about 147 frost-free days for gardens, shorter than 83% of U.S. towns.
Heating and cooling a home in Harper
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Harper, 89% of that work is heating and 11% 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 Harper 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 Harper averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.2°). The shift is larger than in 57% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Harper’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. July swings the most: between 1991 and 2020 its average temperature ranged from 63° to 80°. September is the most reliable, staying within 8°.
Common questions about Harper’s climate
What is the coldest month in Harper?
December, with a typical high of 39° and a low of 20°.
What is the hottest month in Harper?
July, with a typical high of 94° and a low of 56°. About 49 days a year reach 90°.
How much snow does Harper get?
About 6 inches in a normal winter, most of it in December.
When is the first frost in Harper?
In half of years the first 32° night comes by October 3, and the last spring frost by May 7.
What is the rainiest month in Harper?
December, with 1.1 inches of rain and melted snow. The year totals 8 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Harper itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Owyhee Dam, OR (24 mi, snow) and Westfall, OR (10 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.