Santiago has mild winters and cool summers, with plenty of rain
A typical July afternoon reaches 66°, a January night drops to 36°, and about 1 inches of snow falls in a normal winter.
A year in Santiago at a glance
Each month’s typical high and low, and what it brings.
What stands out about Santiago’s climate
Read from where Santiago sits among Washington’s towns. The page puts what stands out first.
What a year in Santiago feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
1 inches of snow, 96 of rain and melt
January is the wettest month and July the driest. Rain or snow falls on about 175 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
About 1.0" in a normal year, so most winters see none.
About 180 frost-free days a year
In half of years the last 32° night comes by April 26 and the first by October 22.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Living with Santiago’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
180 frost-free days. The last frost comes by Apr 26 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 22.
About 1" in a normal winter.
Months averaging under 55° run from October through May. Heating is 100% of the year’s heating-and-cooling load.
About 2 days a year reach 90°, and July afternoons average 66°.
The nicest months are June, July, August and September. 1.3 miles of trails are waiting.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →Warmer than it used to be
The last 30 years in Santiago averaged 1.0° warmer than the 1900s. The biggest change is in January (+2.6°).
A smaller shift than in 73% of U.S. towns.
Change by month
How Santiago compares
Against every U.S. town on TownTapestry, each counted once, with its place in Washington.
Santiago 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° | 36° | 14.8" | 0.5" | 21 | 0 | 37° – 47° |
| February | 50° | 36° | 8.8" | 0 | 17 | 0 | 37° – 49° |
| March | 52° | 37° | 11.0" | 0 | 20 | 0 | 41° – 49° |
| April | 56° | 40° | 7.4" | 0 | 17 | 0 | 43° – 53° |
| May | 60° | 44° | 4.2" | 0 | 12 | 0 | 49° – 56° |
| June | 63° | 48° | 3.3" | 0 | 11 | 0 | 52° – 58° |
| July | 66° | 50° | 1.4" | 0 | 6 | 0 | 56° – 61° |
| August | 67° | 51° | 2.2" | 0 | 6 | 0 | 57° – 61° |
| September | 66° | 48° | 3.9" | 0 | 10 | 0 | 55° – 60° |
| October | 59° | 43° | 10.1" | 0 | 16 | 0 | 48° – 57° |
| November | 52° | 39° | 14.3" | 0.1" | 20 | 0 | 41° – 50° |
| December | 48° | 35° | 14.2" | 0.4" | 20 | 0 | 38° – 45° |
| Year | 57° | 42° | 95.6" | 1.0" | 175 | 0 |
Heating and cooling a home in Santiago
100% of the work is heating, so the furnace matters far more than the air conditioner.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 37° to 49°. August is the most reliable, staying within 5°.
Common questions about Santiago’s climate
What is the coldest month in Santiago?
December, with a typical high of 48° and a low of 35°.
What is the hottest month in Santiago?
August, with a typical high of 67° and a low of 51°. About 2 days a year reach 90°.
How much snow does Santiago get?
About 1 inches in a normal winter, most of it in January.
When is the first frost in Santiago?
In half of years the first 32° night comes by October 22, and the last spring frost by April 26.
What is the rainiest month in Santiago?
January, with 14.8 inches of rain and melted snow. The year totals 96 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Santiago.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Santiago itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Humptulips Salmon Hatchery, WA (12 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Today’s forecast: National Weather Service.