June through August, with peak conditions in July-August. June-August offers warm, dry weather ideal for outdoor exploration; minimal rainfall; Portland's rose gardens (over 10,000 bushes) are in full bloom; major festivals including Rose Festival (May-June), Oregon Brewers Festival (July), and Waterfront Blues Festival (July 4th weekend); note that August-September can occasionally bring wildfire smoke from Eastern Oregon or California
| Month | High (°F) | Low (°F) | Notes |
|---|---|---|---|
| Jan | 47 | 36 | cool & wet |
| Feb | 50 | 36 | cool & wet |
| Mar | 55 | 38 | cool & wet |
| Apr | 60 | 42 | mild & wet |
| May | 68 | 48 | mild & changeable |
| Jun | 74 | 53 | warm & changeable |
| Jul | 84 | 58 | warm & sunny |
| Aug | 85 | 59 | warm & sunny |
| Sep | 77 | 54 | warm & mostly dry |
| Oct | 64 | 47 | mild & changeable |
| Nov | 52 | 40 | cool & wet |
| Dec | 46 | 35 | cool & wet |