St. Helens, OR climate
St. Helens has mild winters and pleasant summers. A typical July afternoon reaches 81°, a January night drops to 34°, and about 1 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in St. Helens feels like
Winter
Spring
Summer
Fall
St. Helens 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° | 34° | 6.1" | 0.5" | 21 | 0 | 33° – 45° |
| February | 51° | 34° | 4.5" | 0.3" | 18 | 0 | 38° – 48° |
| March | 56° | 37° | 4.5" | 0.2" | 21 | 0 | 43° – 52° |
| April | 61° | 40° | 3.5" | 0 | 18 | 0 | 46° – 55° |
| May | 68° | 46° | 2.5" | 0 | 14 | 0 | 52° – 62° |
| June | 73° | 51° | 1.7" | 0 | 11 | 0 | 58° – 67° |
| July | 81° | 54° | 0.5" | 0 | 4 | 0 | 62° – 71° |
| August | 81° | 54° | 0.6" | 0 | 4 | 0 | 64° – 71° |
| September | 76° | 50° | 1.7" | 0 | 9 | 0 | 59° – 65° |
| October | 63° | 44° | 3.7" | 0 | 16 | 0 | 49° – 58° |
| November | 52° | 38° | 6.4" | 0 | 21 | 0 | 39° – 50° |
| December | 45° | 34° | 7.1" | 0.4" | 22 | 0 | 35° – 43° |
| Year | 63° | 43° | 42.7" | 1.4" | 179 | 0 |
“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 St. Helens
St. Helens 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 179 days a year.
About 209 frost-free days a year
In half of years the last 32° night comes by April 10 and the first one by November 2. That leaves about 209 frost-free days for gardens, longer than 78% of U.S. towns.
Heating and cooling a home in St. Helens
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In St. Helens, 93% of that work is heating and 7% 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 St. Helens 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 St. Helens averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.1°). The shift is larger than in 56% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at St. Helens’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. January swings the most: between 1991 and 2020 its average temperature ranged from 33° to 45°. September is the most reliable, staying within 6°.
Common questions about St. Helens’s climate
What is the coldest month in St. Helens?
December, with a typical high of 45° and a low of 34°.
What is the hottest month in St. Helens?
August, with a typical high of 81° and a low of 54°. About 14 days a year reach 90°.
How much snow does St. Helens get?
About 1 inches in a normal winter, most of it in January.
When is the first frost in St. Helens?
In half of years the first 32° night comes by November 2, and the last spring frost by April 10.
What is the rainiest month in St. Helens?
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 St. Helens itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Battle Ground, WA (15 mi, snow) and Scappoose Ind Airport, OR (6 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.