Johnson, OR climate
Johnson has mild winters and pleasant summers. A typical July afternoon reaches 82°, a January night drops to 37°, and about 4 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Johnson feels like
Winter
Spring
Summer
Fall
Johnson 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 | 47° | 37° | 5.9" | 1.3" | 20 | 1 | 34° – 46° |
| February | 51° | 37° | 4.4" | 1.4" | 16 | 1 | 37° – 50° |
| March | 57° | 39° | 4.6" | 0 | 18 | 0 | 45° – 53° |
| April | 62° | 42° | 3.6" | 0 | 17 | 0 | 47° – 57° |
| May | 69° | 48° | 2.6" | 0 | 12 | 0 | 53° – 63° |
| June | 74° | 52° | 1.7" | 0 | 9 | 0 | 59° – 69° |
| July | 82° | 56° | 0.4" | 0 | 3 | 0 | 63° – 72° |
| August | 82° | 56° | 0.6" | 0 | 3 | 0 | 65° – 72° |
| September | 76° | 52° | 1.6" | 0 | 7 | 0 | 60° – 66° |
| October | 64° | 45° | 4.0" | 0 | 13 | 0 | 51° – 59° |
| November | 53° | 40° | 6.4" | 0 | 19 | 0 | 41° – 52° |
| December | 46° | 36° | 7.1" | 0.9" | 20 | 0 | 37° – 44° |
| Year | 63° | 45° | 42.9" | 3.6" | 155 | 2 |
“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 Johnson
Johnson gets 43 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 155 days a year.
About 244 frost-free days a year
In half of years the last 32° night comes by March 18 and the first one by November 18. That leaves about 244 frost-free days for gardens, longer than 89% of U.S. towns.
Heating and cooling a home in Johnson
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Johnson, 88% of that work is heating and 12% 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 Johnson 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 Johnson averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.0°). The shift is larger than in 60% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Johnson’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 37° to 50°. September is the most reliable, staying within 6°.
Common questions about Johnson’s climate
What is the coldest month in Johnson?
December, with a typical high of 46° and a low of 36°.
What is the hottest month in Johnson?
August, with a typical high of 82° and a low of 56°. About 20 days a year reach 90°.
How much snow does Johnson get?
About 4 inches in a normal winter, most of it in February.
When is the first frost in Johnson?
In half of years the first 32° night comes by November 18, and the last spring frost by March 18.
What is the rainiest month in Johnson?
December, with 7.1 inches of rain and melted snow. The year totals 43 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Johnson itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Portland Kgw-tv, OR (9 mi, snow) and Oregon City, OR (4 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.