The best time to visit Pacific Northwest

Temperate rainforest, volcanoes and two coffee-soaked cities, with a summer that is reliably dry and short. Daytime highs in the Pacific Northwest run from about 6 °C in January to 25 °C in August, an annual range of roughly 19 °C.

Measured against a hiking trip, the conditions hold up May to June and September. June is the most consistent single month: highs near 21 °C, nights around 11 °C, and roughly 50 mm of rain across the month.

The binding constraint here is rainfall and temperature — that is what rules months out, not any composite judgement. Rainfall is sharply seasonal: December averages 225 mm against 24 mm in August, so the wet season is the real planning constraint rather than heat or cold. January is the weakest month on these criteria.

July, August sit just outside the window — part of the month works and part does not. These are usually the interesting weeks: conditions are close to the peak-season answer while prices and crowds are not. The map lets you check them fortnight by fortnight rather than trusting a monthly average.

What the Pacific Northwest is known for

Mount Rainier at 4,392 m carries more glacier ice than any other peak in the contiguous United States
Olympic National Park spans rainforest, alpine ridge and wild Pacific coast in one park
The North Cascades hold hundreds of glaciers, more than anywhere else in the lower 48
July to September is genuinely dry here; the rest of the year is not
The San Juan Islands sit in a rain shadow and get noticeably less rain than Seattle

Month by month

Month	High °C	Low °C	Precip mm	Wet days
January	6	1	189	19.0
February	8	1	151	16.7
March	10	2	148	19.2
April	13	5	117	16.3
May	17	8	84	12.9
June	21	11	50	10.1
July	24	13	28	4.5
August	25	14	24	4.6
September	21	12	60	8.1
October	15	8	138	14.5
November	9	4	198	18.4
December	6	2	225	19.5

Ticked rows are months where every hard requirement for a hiking trip is met across at least half the month.

By trip type

Hiking	May to June and September
City	May to September

Each row applies that trip type's own hard limits to the same climate data.

Open Pacific Northwest on the map →

Valley Creek Estuary Park in Port Angeles, Washington. Taken from the observation tower, facing Friendship Bri © Evvekk, CC0 · cropped and resized · Wikimedia Commons

Crew members from Coast Guard Station Bellingham, Wash., assist Chiara D’Angelo, an activist, down from the an © Petty Officer 3rd Class Katelyn Shearer. U.S. Coast Guard District 13., Public domain · cropped and resized · Wikimedia Commons

Nearby regions

Figures are 30-year climatology sampled at Seattle, Portland, Port Angeles, Bellingham and Hood River, averaged across those locations, from ERA5-Land reanalysis fitted with a harmonic seasonal cycle and a trend term, evaluated for 2026. Sampling named towns rather than averaging the whole region avoids blending valley and mountain conditions into a figure true of neither. Cells are about 0.08° wide, from ERA5-Land's 0.1° grid, which is itself driven by a 0.25° (~28 km) atmospheric reanalysis — so individual valleys, sheltered bays and single summits are not resolved. In steep terrain read these as conditions for the wider area rather than for one village. They describe typical conditions, not a forecast. Read how the climatology is built.