Portland, Oregon climate: Normal weather by month, frost dates and records

What is the weather like in Portland each month?

August is the warmest month, with normal highs of 82°F; December the coldest, with normal lows of 36°F. The most precipitation falls in December (5.77 in), the least in July (0.51 in).

Each month has its own page with the day-by-day normals, the month's records and its recent years:

• Jan
• Feb
• Mar
• Apr
• May
• Jun
• Jul
• Aug
• Sep
• Oct
• Nov
• Dec

When is the best weather to visit Portland?

Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (4).

That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.

When is the last frost in Portland?

In Portland, the last spring frost (32°F) comes after March 13 in half of years and after April 1 in one year in ten; the first autumn frost comes before November 19 in half of years and before October 29 in one year in ten.

Last spring frost, half of years after

March 131 year in 10 after April 1; 9 in 10 after February 22

First autumn frost, half of years before

November 191 year in 10 before October 29; 9 in 10 before December 10

NOAA puts the median frost-free season at 247 days, and the season without a hard freeze (28°F) at 298 days.

A hard freeze (28°F) comes after February 16 in half of springs and before December 5 in half of autumns.

The USDA's 2023 Plant Hardiness Zone Map puts Portland in zones 8b to 9a across its 27 ZIP code areas (9a in 97203, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Portland's NOAA station is in zone 9a: the coldest night of a typical year reaches 21°F (30 complete years).

Frost dates for every NOAA station in Oregon · Frost dates by ZIP code

What hardiness zone is each Portland ZIP code in?

The USDA's 2023 map gives each ZIP code area one zone. Portland's 27 ZIP code areas run from zone 8b to 9a: 9 in 8b and 18 in 9a. Each ZIP's frost dates are in the frost tool.

How hot and how cold does it get in Portland?

In a normal year in Portland, 15 days a year reach 90°F (1 of them 100°F or more), 32 nights fall to 32°F or colder and 157 days bring measurable precipitation.

Days at 90°F or more

15a normal year

Days at 100°F or more

1a normal year

Nights at 32°F or colder

32a normal year

Days that stay below freezing

2high of 32°F or less

Days with 0.01 inch of precipitation

157a normal year

Days with 1 inch of snow or more

1a normal year

The highest temperature in Portland's official record (kept by the National Weather Service since 1940) is 116°F, on June 28, 2021; the lowest is −3°F, on February 2, 1950.

The wettest calendar year on that record is 1996, with 63.20 in; the snowiest season is 1949–50, with 44.5 inches.

How humid and windy is Portland, and how clear are its skies?

The summer (June-August) dew point averages 53°F. The muggiest month is July, with an average dew point of 55°F; the driest air comes in December (35°F). December is the windiest month (9.4 mph on average), and July has the most clear or nearly clear hours (60%).

How sunny is Portland?

Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Portland, 3.7 kWh per square metre a day. July is the sunniest month (83%) and December the cloudiest (52%). Among the 459 U.S. places of 50,000 or more, that ranks tied 428th (with 16 others) in sunshine.

How much heating and cooling does Portland need?

A normal year in Portland brings 4,104 heating degree days, 24% fewer than the median U.S. place (5,373), and 508 cooling degree days, 44% fewer than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,832 growing degree days a year above 50°F.

Has Portland been warmer than normal lately?

2025 averaged 56.8°F, 1.7°F above the 1991-2020 normal of 55.1°F. 5 of the 5 complete years since 2021 ran warmer than the normal.

Over 142 complete years from 1873 to 2025, the station's annual mean temperature rose at a fitted 1.8°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.

Which places near Portland share this climate record?

10 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.

• Orchards, WA29,716 people · 8 mi NE
• Five Corners, WA21,444 people · 7 mi N
• Salmon Creek, WA19,594 people · 9 mi N
• Minnehaha, WA12,080 people · 5 mi N
• Mount Vista, WA10,635 people · 10 mi N
• Barberton, WA8,213 people · 9 mi N
• Lake Shore, WA6,601 people · 8 mi NW
• Hockinson, WA5,993 people · 11 mi NE
• Brush Prairie, WA2,563 people · 10 mi N
• Meadow Glade, WA2,534 people · 11 mi N

What do Portland's other NOAA stations record?

3 more NOAA stations keep 1991-2020 normals in or near Portland. This page uses Portland International Airport; the others differ by site and elevation, and the linked ones have pages of their own:

Nearby and next

• Portland in OctoberThis month day by day, its records and recent years
• Oregon climateThe statewide normals and every place in the state
• Vancouver, WA4 miles from this station, 54.0°F a year
• Hazel Dell, WA6 miles from this station, 51.0°F a year
• Portland Troutdale Airport, OR10 miles from this station, 54.7°F a year
• Troutdale, OR11 miles from this station, 53.4°F a year
• Compare two placesMonth by month, side by side

Download these normals (CSV) · JSON · How these figures are made