Santiam Wagon Road · Photo: Breton Friel and John Ferguson, United States Forest Service · Public domainCascadia is among the wettest of U.S. towns: 66 inches of precipitation a year
On a normal January night the air cools to about 35°. Precipitation peaks in December and eases off in July. Its July afternoons stay fresher than in 88% of U.S. towns. Garden planting can start around April 12; autumn frost returns near October 28.
A year in Cascadia at a glance
Each month’s typical high and low, and what it brings.
What stands out about Cascadia’s climate
Compared with towns across the U.S., with Cascadia’s place in Oregon beside it.
What a year in Cascadia feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 197 frost-free days a year
In half of years the last 32° night comes by April 12 and the first by October 28. Day counts come from NOAA’s station at Cascadia, OR, 1.1 miles from the town’s center, 190 ft lower; frost dates and degree days from Foster Dam, OR, 9 miles away.
The 2023 USDA map puts Cascadia’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 66 inches of rain a year
December is the wettest month and July the driest. Rain falls on about 159 days a year. Snow is rare: about 0.1" in a normal year at Foster Dam, OR, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Cascadia
95% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Foster Dam, OR.
Living with Cascadia’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
197 frost-free days in zone 8b. The last frost comes by Apr 12 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 28.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 12 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Cascadia from natural hazards, river flooding is the largest share (82%); heat waves, cold waves, winter storms and ice storms together are 5%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Cascadia and similar climates
TownRatings has no climate map of the towns around Cascadia yet.
Climates most like Cascadia’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 |
|---|---|---|---|---|
| Cascadia, OR | 35° | 81° | 66" | 0.1" |
| East Flat Rock, NC | 29° | 83° | 64" | 6.7" |
| Shelton, WA | 34° | 77° | 62" | 4.4" |
| Signal Mountain, TN | 29° | 85° | 62" | 4.3" |
| Fort Payne, AL | 31° | 86° | 60" | 5.0" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Cascadia averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.0°).
A smaller shift than in 60% 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 Cascadia compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Cascadia’s place among Oregon’s.
Cascadia weather by month
Highs, lows and precipitation from NOAA’s grid at Cascadia’s center; snow, wet days and snow on the ground from Foster Dam, OR. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 46° | 35° | 8.7" | 0.1" | 19 | 0 | 35° – 45° |
| February | 50° | 34° | 6.8" | 0.0" | 17 | 0 | 35° – 47° |
| March | 54° | 36° | 7.6" | 0.0" | 19 | 0 | 41° – 51° |
| April | 59° | 38° | 6.5" | 0.0" | 18 | 0 | 44° – 54° |
| May | 66° | 43° | 4.3" | 0.0" | 13 | 0 | 50° – 59° |
| June | 72° | 48° | 2.8" | 0.0" | 9 | 0 | 56° – 67° |
| July | 81° | 51° | 0.6" | 0.0" | 3 | 0 | 61° – 70° |
| August | 81° | 50° | 0.7" | 0.0" | 3 | 0 | 62° – 71° |
| September | 75° | 47° | 2.4" | 0.0" | 7 | 0 | 58° – 64° |
| October | 62° | 41° | 5.6" | 0.0" | 13 | 0 | 48° – 57° |
| November | 51° | 37° | 9.4" | 0.0" | 18 | 0 | 38° – 48° |
| December | 44° | 34° | 10.4" | 0.0" | 20 | 0 | 34° – 43° |
| Year | 62° | 41° | 65.7" | 0.1" | 159 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 35° to 47°. September is the most reliable, staying within 6°.
Where Cascadia’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 Cascadia’s center.
- Snow: Foster Dam, OR.
- Frost dates, heating and cooling: Foster Dam, OR, 9 miles away.
- Freezing nights, 90° and 100° days: Cascadia, OR, 1.1 miles from the town’s center, 190 ft lower; 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 Cascadia’s climate
What is the weather like in Cascadia?
A typical July afternoon reaches 81°, a January night drops to 35°, and snow is almost unheard of. Milder January nights than 79% of U.S. towns; cooler July afternoons than 88% of U.S. towns.
How cold does it get in Cascadia in winter?
December nights average 34°. About 79 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 34°.
How much snow does Cascadia get?
About 0.1 inches in a normal winter at Foster Dam, OR, so most winters see none.
How hot does it get in Cascadia?
July, with a typical high of 81° and a low of 51°. About 8 days a year reach 90° (Foster Dam, OR).
When is the first and last frost in Cascadia?
In half of years the last spring frost (32°) comes by April 12 and the first fall frost by October 28, about 197 frost-free days, at Foster Dam, OR.
What growing zone is Cascadia 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 Cascadia?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Cascadia getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Cascadia.
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.