What is the hottest month in Portland?

August is Portland's hottest month, with the highest average daily high of the year. The month-by-month table above shows Portland's exact average high and low for each month, based on the 1991–2020 climate normals — the standard 30-year reference period meteorologists use.

What is the coldest month in Portland?

January is Portland's coldest month, with the lowest average daily low of the year. The averages-by-month chart above gives the exact average high and low for every month, so you can see how cold a typical winter day runs.

How much does it rain in Portland?

Portland's total annual precipitation and its wettest and driest months are shown in the rainfall-by-month section above. Those figures are 1991–2020 normals — the average monthly precipitation total across that 30-year window — so they reflect a typical year rather than any single wet or dry season.

What months are best to visit Portland?

The most comfortable months in Portland are usually the shoulder seasons — spring and fall — when temperatures sit between the summer peak and winter low and rainfall is moderate. Compare the average high, low, and precipitation for each month in the table above to pick the window that fits the weather you want.

Has Portland gotten hotter?

Yes. The warming-stripes chart above plots Portland's annual mean temperature for every complete year of station data from 1939 to 2025, and the trend line fitted to 1939–2025 rises about 3.1°F (+0.36°F per decade) — recent decades average warmer than the start of that window.

What is the record high temperature in Portland?

Portland's all-time record high — the hottest single day in the station record — is shown in the records section above, along with the date it occurred. Records are drawn from the nearest long-term weather station's full daily history, which begins in 1938, so they capture the most extreme heat on record, not just a typical summer day.

What is the record low temperature in Portland?

Portland's all-time record low and the date it was set appear in the records section above. Like the record high, it comes from the station's full daily history back to 1938, so it reflects the coldest day on record rather than an average winter low.

Portland, Oregon Climate

Portland weather by month — average highs and lows, rainfall, all-time records, and the warming record since 1939

Hottest month: 82°FAugust average high
Coldest month: 36°FJanuary average low
Precipitation: 36.9 ina year
Snowfall: 4.2 ina year

1991–2020 NOAA climate normals

At 2:22 AM PDT on Sep 21 it was 58°F in Portland — 2° above the 56°F typical for that hour (estimated from the Sep 21 normal high of 74°F and low of 53°F, interpolated from the monthly normals).

Portland weather by month

Average high, low, and rainfall for every month, from Portland’s 1991–2020 climate normals, the standard 30-year reference period. Each band runs from the month’s average low to its average high: a tall band is a big day-to-night swing.

48°36°

5.0″Jan

52°37°

3.7″Feb

57°40°

4.0″Mar

62°44°

2.9″Apr

69°49°

2.5″May

74°54°

1.6″Jun

82°59°

0.5″Jul

82°59°

0.5″Aug

77°54°

1.5″Sep

64°47°

3.4″Oct

54°41°

5.5″Nov

47°36°

5.8″Dec

Average high → low (°F)Rainfall (inches)1991–2020 normals

Portland monthly weather averages — average high, average low, and rainfall for each month, from the 1991–2020 U.S. Climate Normals (NOAA).
Month	Avg High	Avg Low	Rainfall
January	48°F	36°F	5.0 in
February	52°F	37°F	3.7 in
March	57°F	40°F	4.0 in
April	62°F	44°F	2.9 in
May	69°F	49°F	2.5 in
June	74°F	54°F	1.6 in
July	82°F	59°F	0.5 in
August	82°F	59°F	0.5 in
September	77°F	54°F	1.5 in
October	64°F	47°F	3.4 in
November	54°F	41°F	5.5 in
December	47°F	36°F	5.8 in
Annual	64°F	46°F	36.9 in

Portland’s warming record since 1939

Portland has warmed 3.1°F since 1939 (+0.36°F per decade, 1939–2025 trend)

Not what a typical year looks like, but how the typical year has changed. Each stripe is one complete year’s average temperature at the station, 1939 to 2025, colored against the mean of those years: blue for cooler years, red for warmer ones. The figure under the stripes is the least-squares trend line fitted to 1939–2025 — Portland averages about 3.1°F warmer by that trend than in 1939.

Compared with the national rankingThe fastest-warming cities ranking fits every city to the same years, 1970–2025, so rates compare like for like. Over that window Portland warms at +0.48°F per decade, #45 of 66. The figure above uses the station’s own record, 1939–2025, so the two rates differ.

Portland rainfall by month

Portland averages 36.9 inches of precipitation a year. The wettest month is December and the driest is July.

Portland also averages 4.2 inches of snowfall a year.

Portland temperature records

All-time record high: 116°Fset June 28, 2021
All-time record low: -3°Fset February 2, 1950

Records are drawn from the nearest long-term weather station’s full daily history, so they capture the most extreme single day Portland has recorded — not a typical seasonal high or low.

Frequently asked

What is the hottest month in Portland?: August is Portland's hottest month, with the highest average daily high of the year. The month-by-month table above shows Portland's exact average high and low for each month, based on the 1991–2020 climate normals — the standard 30-year reference period meteorologists use.
What is the coldest month in Portland?: January is Portland's coldest month, with the lowest average daily low of the year. The averages-by-month chart above gives the exact average high and low for every month, so you can see how cold a typical winter day runs.
How much does it rain in Portland?: Portland's total annual precipitation and its wettest and driest months are shown in the rainfall-by-month section above. Those figures are 1991–2020 normals — the average monthly precipitation total across that 30-year window — so they reflect a typical year rather than any single wet or dry season.
What months are best to visit Portland?: The most comfortable months in Portland are usually the shoulder seasons — spring and fall — when temperatures sit between the summer peak and winter low and rainfall is moderate. Compare the average high, low, and precipitation for each month in the table above to pick the window that fits the weather you want.
Has Portland gotten hotter?: Yes. The warming-stripes chart above plots Portland's annual mean temperature for every complete year of station data from 1939 to 2025, and the trend line fitted to 1939–2025 rises about 3.1°F (+0.36°F per decade) — recent decades average warmer than the start of that window.
What is the record high temperature in Portland?: Portland's all-time record high — the hottest single day in the station record — is shown in the records section above, along with the date it occurred. Records are drawn from the nearest long-term weather station's full daily history, which begins in 1938, so they capture the most extreme heat on record, not just a typical summer day.
What is the record low temperature in Portland?: Portland's all-time record low and the date it was set appear in the records section above. Like the record high, it comes from the station's full daily history back to 1938, so it reflects the coldest day on record rather than an average winter low.