Herron Island, WA climate
Herron Island has mild winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 77°, a January night drops to 35°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Herron Island feels like
Winter
Spring
Summer
Fall
Herron Island 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° | 35° | 8.3" | 0 | 20 | 0 | 37° – 45° |
| February | 50° | 35° | 5.3" | 0 | 16 | 0 | 36° – 48° |
| March | 54° | 37° | 6.1" | 0 | 19 | 0 | 42° – 50° |
| April | 59° | 40° | 4.1" | 0 | 16 | 0 | 45° – 55° |
| May | 67° | 46° | 2.3" | 0 | 12 | 0 | 52° – 60° |
| June | 71° | 50° | 1.6" | 0 | 9 | 0 | 57° – 66° |
| July | 77° | 54° | 0.7" | 0 | 5 | 0 | 61° – 69° |
| August | 78° | 54° | 1.0" | 0 | 6 | 0 | 62° – 69° |
| September | 72° | 50° | 1.9" | 0 | 7 | 0 | 58° – 64° |
| October | 60° | 44° | 5.4" | 0 | 14 | 0 | 49° – 57° |
| November | 51° | 38° | 8.3" | 0 | 19 | 0 | 41° – 49° |
| December | 46° | 35° | 8.7" | 0.3" | 19 | 0 | 36° – 43° |
| Year | 61° | 43° | 53.7" | 0.3" | 161 | 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 Herron Island
Herron Island gets 54 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 161 days a year.
About 254 frost-free days a year
In half of years the last 32° night comes by March 11 and the first one by November 21. That leaves about 254 frost-free days for gardens, longer than 91% of U.S. towns.
Heating and cooling a home in Herron Island
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Herron Island, 97% of that work is heating and 3% 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 Herron Island 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 Herron Island averaged 0.8° warmer than the 1900s. The biggest change is in January (+2.4°). The shift is smaller than in 84% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Herron Island’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 36° to 48°. September is the most reliable, staying within 6°.
Common questions about Herron Island’s climate
What is the coldest month in Herron Island?
December, with a typical high of 46° and a low of 35°.
What is the hottest month in Herron Island?
August, with a typical high of 78° and a low of 54°. About 2 days a year reach 90°.
How much snow does Herron Island get?
Almost none. A normal year brings 0.3 inches.
When is the first frost in Herron Island?
In half of years the first 32° night comes by November 21, and the last spring frost by March 11.
What is the rainiest month in Herron Island?
December, with 8.7 inches of rain and melted snow. The year totals 54 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Herron Island itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Wauna 3 W, WA (9 mi, snow) and Tacoma Narrows Airport, WA (12 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.