Photo: Flytzjl93 · CC BY-SA 4.0Roslyn’s winters are milder than most of the U.S.; July afternoons average 73°
A typical July afternoon reaches 73°, a January night drops to 24°.
A year in Roslyn at a glance
Each month’s typical high and low, and what it brings.
What stands out about Roslyn’s climate
Compared with towns across the U.S., with Roslyn’s place in Washington beside it.
What a year in Roslyn feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 154 frost-free days a year
In half of years the last 32° night comes by May 14 and the first by October 17. Frost and day counts come from NOAA’s station at Stampede Pass, WA, 9 miles from the town’s center, 460 ft higher.
The 2023 USDA map puts Roslyn’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 4°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 55 inches of rain a year
December is the wettest month and July the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Roslyn
99% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through June.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Stampede Pass, WA.
Living with Roslyn’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
154 frost-free days in zone 7a. The last frost comes by May 14 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 17.
Months with highs of 62–84° and lows of 40° or more: June, July, August and September. 19 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Roslyn from natural hazards, wildfire is the largest share (48%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Roslyn and similar climates
TownRatings has no climate map of the towns around Roslyn yet.
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 Roslyn averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.9°).
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 Roslyn compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Roslyn’s place among Washington’s.
Roslyn weather by month
Highs, lows and precipitation from NOAA’s grid at Roslyn’s center. 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 33° | 24° | 9.4" | 22° – 35° |
| February | 37° | 25° | 6.1" | 23° – 38° |
| March | 43° | 28° | 5.5" | 30° – 42° |
| April | 49° | 32° | 3.3" | 35° – 47° |
| May | 58° | 38° | 2.4" | 43° – 53° |
| June | 63° | 43° | 1.6" | 49° – 62° |
| July | 73° | 49° | 0.7" | 53° – 65° |
| August | 73° | 50° | 0.8" | 56° – 66° |
| September | 65° | 45° | 1.7" | 51° – 60° |
| October | 52° | 37° | 5.6" | 40° – 49° |
| November | 39° | 29° | 8.8" | 29° – 39° |
| December | 32° | 24° | 9.4" | 24° – 32° |
| Year | 51° | 35° | 55.2" |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 23° to 38°. December is the most reliable, staying within 8°.
Where Roslyn’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 Roslyn’s center.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Stampede Pass, WA, 9 miles from the town’s center, 460 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 Roslyn’s climate
What is the weather like in Roslyn?
A typical July afternoon reaches 73°, a January night drops to 24°. Milder January nights than 60% of U.S. towns; cooler July afternoons than all but 123 U.S. towns.
How cold does it get in Roslyn in winter?
December nights average 24°. About 165 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 24°.
How hot does it get in Roslyn?
July, with a typical high of 73°. 90° days are rare: none in a normal year at Stampede Pass, WA.
When is the first and last frost in Roslyn?
In half of years the last spring frost (32°) comes by May 14 and the first fall frost by October 17, about 154 frost-free days, at Stampede Pass, WA.
What growing zone is Roslyn in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 4°.
What is the best time of year to visit Roslyn?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Roslyn 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 Roslyn.
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.