Aubrey R. Watzek House · Photo: Visitor7 · CC BY-SA 3.0July in Portland stays fresher than in 88% of U.S. towns
In January the night’s low is typically 36°. Expect the heaviest rain or snow in December and the lightest in July. Winters are mild: January nights here are milder than in 83% of U.S. towns. Plan time outside from May to October, when highs sit at 64–82°.
A year in Portland at a glance
Each month’s typical high and low, and what it brings.
What stands out about Portland’s climate
Compared with towns across the U.S., with Portland’s place in Oregon beside it.
What a year in Portland feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 247 frost-free days a year
In half of years the last 32° night comes by March 13 and the first by November 19. Frost and day counts come from NOAA’s station at Portland International Airport, 4 miles from the city’s center point, 170 ft lower.
The 2023 USDA map puts Portland’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 21°. 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 International Airport, falls mostly in January. Precipitation (rain plus melted snow) adds up to 41 inches a year; December is the wettest month and July the driest. Rain or snow falls on about 157 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Portland
89% 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 International Airport.
Living with Portland’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
247 frost-free days in zone 9a. The last frost comes by Mar 13 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 19.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 246 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Portland from natural hazards, earthquakes are the largest share (77%); heat waves, cold waves, winter storms and ice storms together are 4%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Portland and its neighbors
Every town next door is within a degree of Portland in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Portland’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 |
|---|---|---|---|---|
| Portland, OR | 36° | 81° | 41" | 4.2" |
| 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 Portland averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.1°).
A smaller shift than in 53% 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. In a city of 635,000 people, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
How Portland compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Portland’s place among Oregon’s.
Portland weather by month
Highs, lows and precipitation from NOAA’s grid at Portland’s center; snow, wet days and snow on the ground from Portland International Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 47° | 36° | 5.8" | 1.7" | 19 | 1 | 34° – 46° |
| February | 51° | 36° | 4.2" | 1.2" | 16 | 1 | 37° – 49° |
| March | 56° | 39° | 4.4" | 0.1" | 18 | 0 | 44° – 52° |
| April | 61° | 42° | 3.3" | 0.0" | 17 | 0 | 47° – 56° |
| May | 69° | 47° | 2.5" | 0.0" | 13 | 0 | 53° – 63° |
| June | 73° | 52° | 1.6" | 0.0" | 9 | 0 | 59° – 69° |
| July | 81° | 56° | 0.4" | 0.0" | 4 | 0 | 63° – 72° |
| August | 82° | 56° | 0.6" | 0.0" | 4 | 0 | 65° – 72° |
| September | 76° | 52° | 1.6" | 0.0" | 7 | 0 | 60° – 66° |
| October | 64° | 45° | 3.7" | 0.0" | 14 | 0 | 50° – 59° |
| November | 53° | 40° | 6.1" | 0.0" | 18 | 0 | 41° – 52° |
| December | 46° | 36° | 6.8" | 1.2" | 19 | 1 | 36° – 44° |
| Year | 63° | 45° | 41.0" | 4.2" | 157 | 3 |
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°. September is the most reliable, staying within 6°.
Where Portland’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 Portland’s center.
- Snow: Portland International Airport (the official station).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Portland International Airport, 4 miles from the city’s center point, 170 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 Portland’s climate
What is the weather like in Portland?
A typical July afternoon reaches 81°, a January night drops to 36°, and about 4 inches of snow falls in a normal winter. Milder January nights than 83% of U.S. towns; cooler July afternoons than 88% of U.S. towns.
How cold does it get in Portland in winter?
December nights average 36°. About 32 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 36°.
How much snow does Portland get?
About 4.2 inches in a normal winter at Portland International Airport, most of it in January, with snow on the ground about 3 days a year.
How hot does it get in Portland?
July, with a typical high of 81° and a low of 56°. About 15 days a year reach 90° and 1 reach 100° (Portland International Airport).
When is the first and last frost in Portland?
In half of years the last spring frost (32°) comes by March 13 and the first fall frost by November 19, about 247 frost-free days, at Portland International Airport.
What growing zone is Portland in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 21°.
What is the best time of year to visit Portland?
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 Portland getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Portland.
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.