Portland vs Seattle: which is better, month by month

Seattle beats Portland in 3 of 12 months — its lead peaks in August (95 vs 89) — while Portland wins June and September; they are within 3 points in the other 7 months.

Each place is scored under the lens that suits its type. Comfort is SeasonMap's 0–100 estimate from ERA5 climate normals, not a forecast.

Portland

🇺🇸 United States · mild climate

Best month: June 96/100
Months won: 2 of 12

Seattle

🇺🇸 United States · mild climate

Best month: July 97/100
Months won: 3 of 12

Portland vs Seattle — all 12 months

Month	Portland	Seattle	Winner	Gap
January	49Fcold, soaked, clean air	52Dcold, rainy, clean air	Tie	3
February	55Dcold, rainy, clean air	58Dcold, rainy, clean air	Tie	3
March	65Ccool, rainy, clean air	67Ccold, a little rain, clean air	Tie	2
April	76Bcool, rainy, clean air	77Bcool, a little rain, clean air	Tie	1
May	86Anice, a little rain, clean air	85Anice, a little rain, clean air	Tie	1
June	96Swarm, a little rain, clean air	92Snice, dry, clean air	Portland	4
July	92Swarm, dry, clean air	97Swarm, dry, clean air	Seattle	5
August	89Awarm, dry, clean air	95Swarm, dry, clean air	Seattle	6
September	94Swarm, a little rain, clean air	89Anice, a little rain, clean air	Portland	5
October	72Bnice, rainy, clean air	72Bcool, a little rain, clean air	Tie	0
November	57Dcool, soaked, clean air	57Dcold, rainy, clean air	Tie	0
December	45Fcold, soaked, clean air	49Fcold, rainy, clean air	Seattle	4

A month is a tie when the two are within 3 points. The widest gap is August (89 vs 95). Tap a month for that month's temperature, rain, humidity and air quality side by side.