Photo: Tedder · CC BY 3.0Afternoon heat in West Haven-Sylvan trails that of 92% of U.S. towns
Nights in January average 36°. By January nights alone, it runs milder than 82% of U.S. towns. Since 1901–2000, the year has warmed by 1.2°, most of all in January. Central heating does most of its work from November to March, in months below 50° on average.
A year in West Haven-Sylvan at a glance
Each month’s typical high and low, and what it brings.
What stands out about West Haven-Sylvan’s climate
Compared with towns across the U.S., with West Haven-Sylvan’s place in Oregon beside it.
What a year in West Haven-Sylvan feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 280 frost-free days a year
In half of years the last 32° night comes by February 25 and the first by December 1. Frost and day counts come from NOAA’s station at Portland Kgw-tv, OR, 4 miles from the town’s center, 420 ft lower.
The 2023 USDA map puts West Haven-Sylvan’s center in zone 8b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 17°. 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 4 inches of snow a winter
Snow, measured at Portland Kgw-tv, OR, is heaviest from January through February, about 1 inches a month. Precipitation (rain plus melted snow) adds up to 44 inches a year; December is the wettest month and July the driest. Rain or snow falls on about 155 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in West Haven-Sylvan
90% 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 Portland Kgw-tv, OR.
Living with West Haven-Sylvan’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
280 frost-free days in zone 8b. The last frost comes by Feb 25 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Dec 1.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 1.6 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in West Haven-Sylvan from natural hazards, earthquakes are the largest share (47%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →West Haven-Sylvan and its neighbors
Beaverton the hottest July afternoons (81°, 1° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like West Haven-Sylvan’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 |
|---|---|---|---|---|
| West Haven-Sylvan, OR | 36° | 80° | 44" | 3.6" |
| Ben Lomond, CA | 40° | 79° | 43" | 0.0" |
| Redmond, WA | 36° | 76° | 40" | 3.8" |
| Brigantine, NJ | 28° | 83° | 45" | 10" |
| Swannanoa, NC | 27° | 83° | 48" | 2.1" |
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 West Haven-Sylvan averaged 1.2° warmer than the 1900s. The biggest change is in January (+2.9°).
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 West Haven-Sylvan compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with West Haven-Sylvan’s place among Oregon’s.
West Haven-Sylvan weather by month
Highs, lows and precipitation from NOAA’s grid at West Haven-Sylvan’s center; snow, wet days and snow on the ground from Portland Kgw-tv, OR. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 46° | 36° | 6.5" | 1.3" | 20 | 1 | 33° – 45° |
| February | 50° | 36° | 4.8" | 1.4" | 16 | 1 | 36° – 48° |
| March | 55° | 38° | 4.7" | 0.0" | 18 | 0 | 43° – 51° |
| April | 60° | 41° | 3.4" | 0.0" | 17 | 0 | 46° – 55° |
| May | 67° | 46° | 2.5" | 0.0" | 12 | 0 | 52° – 61° |
| June | 72° | 51° | 1.6" | 0.0" | 9 | 0 | 58° – 67° |
| July | 80° | 55° | 0.4" | 0.0" | 3 | 0 | 62° – 71° |
| August | 80° | 55° | 0.6" | 0.0" | 3 | 0 | 64° – 71° |
| September | 75° | 51° | 1.6" | 0.0" | 7 | 0 | 59° – 66° |
| October | 63° | 45° | 3.9" | 0.0" | 13 | 0 | 49° – 58° |
| November | 52° | 39° | 6.7" | 0.0" | 19 | 0 | 40° – 50° |
| December | 46° | 35° | 7.6" | 0.9" | 20 | 0 | 36° – 43° |
| Year | 62° | 44° | 44.0" | 3.6" | 155 | 2 |
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 6°.
Where West Haven-Sylvan’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 West Haven-Sylvan’s center.
- Snow: Portland Kgw-tv, OR.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Portland Kgw-tv, OR, 4 miles from the town’s center, 420 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 West Haven-Sylvan’s climate
What is the weather like in West Haven-Sylvan?
A typical July afternoon reaches 80°, a January night drops to 36°, and about 4 inches of snow falls in a normal winter. Milder January nights than 82% of U.S. towns; cooler July afternoons than 92% of U.S. towns.
How cold does it get in West Haven-Sylvan in winter?
December nights average 35°. About 18 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 36°.
How much snow does West Haven-Sylvan get?
About 3.6 inches in a normal winter at Portland Kgw-tv, OR, heaviest from January through February, about 1 inches a month, with snow on the ground about 2 days a year.
How hot does it get in West Haven-Sylvan?
July, with a typical high of 80° and a low of 55°. About 11 days a year reach 90° (Portland Kgw-tv, OR).
When is the first and last frost in West Haven-Sylvan?
In half of years the last spring frost (32°) comes by February 25 and the first fall frost by December 1, about 280 frost-free days, at Portland Kgw-tv, OR.
What growing zone is West Haven-Sylvan in?
Zone 8b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 17°.
What is the best time of year to visit West Haven-Sylvan?
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 West Haven-Sylvan 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 West Haven-Sylvan.
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.