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Climate in Portland, Oregon: Monthly Weather Averages

By the AverageClimate Editorial Team · Last updated: October 2026

Portland sits at 19 feet above sea level, and its climate, as recorded at the Portland International Airport, OR station, runs to a yearly mean of 55.1°F. The warmest month is August, averaging 70.6°F with typical highs of 82.3°F; the coldest is December, averaging 41.6°F with lows around 36.2°F. Across a normal year the city receives 36.9 in of precipitation and 4.2 in of snow. The full month-by-month picture below comes from the official 1991–2020 U.S. Climate Normals — the 30-year averages the National Weather Service itself uses — so it describes the Portland climate you should actually plan around, whether you are timing a visit, weighing a move, or just settling an argument about which month is best.

Portland climate month by month

The table below is the complete 1991–2020 normals profile for Portland: average high, average low and mean temperature, rainfall, and snowfall for every month. Read down the Mean column to feel the year's rhythm — Portland's temperature range runs from 41.6°F in December to 70.6°F in August.

How to read the colors:below freezingcoldcoolmildwarmhot. Bands are colored by each cell's own temperature, so a whole year reads at a glance.

Portland through the seasons

Winter in Portland averages highs of 46.9–51.5°F and lows of 36.2–36.8°F, a seasonal mean of 42.5°F. The three months together bring 14.5 in of precipitation — about 39% of the city's yearly total — with December the wettest of the three at 5.77 in. Snowfall averages 4.1 in over the season, most of it in January (1.7 in). It is a genuinely cold season — heavy coats, freezing nights, and the year's most changeable weather — without being locked below freezing around the clock.

Spring in Portland averages highs of 56.8–69.3°F and lows of 39.7–49.4°F, a seasonal mean of 53.5°F. The three months together bring 9.4 in of precipitation — about 25% of the city's yearly total — with March the wettest of the three at 3.97 in. Snowfall averages 0.1 in over the season, most of it in March (0.1 in). The season is a transition: the average temperature climbs 11.1°F from March to May, and by late spring Portland is firmly into mild territory.

Summer in Portland averages highs of 74.3–82.3°F and lows of 54.1–58.9°F, a seasonal mean of 68.3°F. The three months together bring 2.7 in of precipitation — about 7% of the city's yearly total — with June the wettest of the three at 1.63 in. It is a warm, usable summer: afternoons are hot enough for swimming and lake or coast time, while evenings usually cool off comfortably.

Fall in Portland averages highs of 53.5–76.7°F and lows of 40.6–54.1°F, a seasonal mean of 56.0°F. The three months together bring 10.4 in of precipitation — about 28% of the city's yearly total — with November the wettest of the three at 5.45 in. Temperatures ease off through the season — the monthly mean drops 18.3°F from September to November — and fall is when Portland's weather turns cooler and wetter, while nights stay mostly frost-free into December.

Best and worst months to visit Portland

Ranking every month by its normals — mild mean temperatures score best, heavy rain and snow count against — the most comfortable months to visit Portland are:

JulyAugustSeptember

July leads the list: average highs of 81.9°F, lows of 58.5°F, and 0.51 in of rain, with snow a non-factor at 0.0 in. The other picks, August and September, offer the same balance in Portland's mild stretch of the year. At the other end, December is usually the month to avoid — the year's heaviest rain, with a mean temperature of 41.6°F and 5.77 in of precipitation plus 1.2 in of snow.

How Portland compares

Across the 114 cities in our dataset, the typical city averages 57.8°F for the year and 35.7 in of precipitation. Portland runs 2.7°F cooler than that typical city and wetter by 1.3 in a year, ranking #65 of 114 for annual warmth and #62 of 114 for precipitation (wettest first). Its year-round temperature swing — warmest month minus coldest — is 29.0°F, which puts it in the moderate, clearly seasonal camp.

Within Oregon, Portland is #2 of 4 for warmth of the cities we track. See the Oregon climate overview for the full state comparison, including Medford (warmest, 55.9°F yearly mean) and Bend (coolest, 47.6°F).

Planning notes for Portland

For anyone relocating: average lows never drop below freezing in any month, so hard freezes are events, not seasons; highs reach the 80s on average in 2 months, but 90°F average highs never arrive; 6 months of the year average between 55°F and 80°F, the band most people find comfortable without heating or cooling. Those four facts, all straight from the normals table above, shape everything from a Portland wardrobe to its utility bills.

Portland climate FAQ

Source: 1991–2020 U.S. Climate Normals, NOAA National Centers for Environmental Information (NCEI) — ncei.noaa.gov. Station: Portland International Airport, OR (USW00024229), elevation 19 ft. Figures checked October 2026.