Charles W. Orton House · Photo: Ben Cody · Public domainAlderton’s winters are milder and less snowy than most of the U.S.
A typical July afternoon reaches 78°, a January night drops to 35°, and about 6 inches of snow falls in a normal winter.
A year in Alderton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Alderton’s climate
Compared with towns across the U.S., with Alderton’s place in Washington beside it.
What a year in Alderton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 202 frost-free days a year
In half of years the last 32° night comes by April 11 and the first by October 30. Frost and day counts come from NOAA’s station at Mcmillin Reservoir, WA, 3 miles from the town’s center, 490 ft higher.
The 2023 USDA map puts Alderton’s center in zone 8b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 18°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 6 inches of snow a winter
Snow, measured at Mcmillin Reservoir, WA, falls mostly in January, November and December. Precipitation (rain plus melted snow) adds up to 40 inches a year; November is the wettest month and July the driest. Rain or snow falls on about 166 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Alderton
98% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Mcmillin Reservoir, WA.
Living with Alderton’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
202 frost-free days in zone 8b. The last frost comes by Apr 11 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 30.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 8.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Alderton from natural hazards, river flooding is the largest share (44%); heat waves, cold waves, winter storms and ice storms together are 14%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Alderton and its neighbors
Every town next door is within a degree of Alderton in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Alderton’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Alderton, WA | 35° | 78° | 40" | 5.6" |
| Silverton, OR | 36° | 81° | 46" | 1.1" |
| Scotts Valley, CA | 39° | 79° | 37" | 0.0" |
| Chatham, MA | 25° | 77° | 44" | 25" |
| Brigantine, NJ | 28° | 83° | 45" | 10" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Alderton averaged 1.1° warmer than the 1900s. The biggest change is in January (+2.7°).
A smaller shift than in 71% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Alderton compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Alderton’s place among Washington’s.
Alderton weather by month
Highs, lows and precipitation from NOAA’s grid at Alderton’s center; snow, wet days and snow on the ground from Mcmillin Reservoir, WA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 47° | 35° | 5.5" | 1.5" | 20 | 2 | 36° – 46° |
| February | 50° | 35° | 3.8" | 0.5" | 15 | 0 | 36° – 48° |
| March | 55° | 38° | 4.3" | 0.6" | 20 | 1 | 42° – 50° |
| April | 60° | 41° | 3.5" | 0.0" | 16 | 0 | 45° – 56° |
| May | 67° | 47° | 2.5" | 0.0" | 13 | 0 | 52° – 60° |
| June | 71° | 51° | 2.0" | 0.0" | 11 | 0 | 58° – 67° |
| July | 78° | 54° | 0.8" | 0.0" | 5 | 0 | 61° – 69° |
| August | 78° | 54° | 1.0" | 0.0" | 5 | 0 | 63° – 70° |
| September | 72° | 50° | 1.7" | 0.0" | 8 | 0 | 58° – 64° |
| October | 61° | 44° | 4.0" | 0.0" | 15 | 0 | 49° – 57° |
| November | 52° | 38° | 6.1" | 1.5" | 19 | 1 | 41° – 50° |
| December | 46° | 35° | 5.5" | 1.5" | 20 | 2 | 36° – 43° |
| Year | 61° | 43° | 40.4" | 5.6" | 166 | 5 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 36° to 48°. September is the most reliable, staying within 7°.
Where Alderton’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Alderton’s center.
- Snow: Mcmillin Reservoir, WA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Mcmillin Reservoir, WA, 3 miles from the town’s center, 490 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Alderton’s climate
What is the weather like in Alderton?
A typical July afternoon reaches 78°, a January night drops to 35°, and about 6 inches of snow falls in a normal winter. Milder January nights than 81% of U.S. towns; cooler July afternoons than 96% of U.S. towns.
How cold does it get in Alderton in winter?
December nights average 35°. About 60 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 36°.
How much snow does Alderton get?
About 5.6 inches in a normal winter at Mcmillin Reservoir, WA, most of it in January, November and December, with snow on the ground about 5 days a year.
How hot does it get in Alderton?
July, with a typical high of 78° and a low of 54°. About 3 days a year reach 90° (Mcmillin Reservoir, WA).
When is the first and last frost in Alderton?
In half of years the last spring frost (32°) comes by April 11 and the first fall frost by October 30, about 202 frost-free days, at Mcmillin Reservoir, WA.
What growing zone is Alderton in?
Zone 8b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 18°.
What is the best time of year to visit Alderton?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Alderton getting warmer?
Yes: 1991–2020 averaged 1.1° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 71% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Alderton.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.