Climate twins of Portland, OR
These are the US cities whose 12-month climate pattern most closely matches Portland's. Each "twin" must be at least 140 miles away to avoid trivial near-neighbor matches. Similarity is computed across all 24 monthly metrics (12 average temperatures + 12 average precipitations), normalized so temperature and precipitation contribute equally.
Side-by-side: Portland vs its climate twin
Top match: Seattle, WA
| Month | Portland | Seattle | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 46.9°F | 37.3°F | 6.36 in | 48.6°F | 36.8°F | 5.21 in |
| February | 50.5°F | 38.8°F | 4.74 in | 50.7°F | 36.8°F | 3.71 in |
| March | 55.8°F | 40.9°F | 4.83 in | 54.8°F | 39.4°F | 3.94 in |
| April | 60.7°F | 44.2°F | 3.63 in | 59.8°F | 43.6°F | 2.89 in |
| May | 68.0°F | 49.4°F | 2.58 in | 66.5°F | 49.3°F | 1.98 in |
| June | 72.9°F | 53.3°F | 1.49 in | 71.2°F | 54.0°F | 1.22 in |
| July | 80.3°F | 57.9°F | 0.43 in | 77.3°F | 57.5°F | 0.56 in |
| August | 80.6°F | 58.6°F | 0.54 in | 77.4°F | 58.1°F | 0.83 in |
| September | 74.9°F | 55.1°F | 1.58 in | 71.7°F | 53.9°F | 1.37 in |
| October | 62.9°F | 47.9°F | 3.96 in | 61.0°F | 46.4°F | 3.49 in |
| November | 52.3°F | 41.6°F | 6.58 in | 53.0°F | 39.9°F | 5.80 in |
| December | 45.9°F | 37.3°F | 7.35 in | 47.8°F | 36.2°F | 5.49 in |
How this is computed
Each city is represented by a 24-dimensional vector: 12 monthly average temperatures and 12 monthly average precipitations. Each dimension is z-score normalized across the population of US cities, so that temperature variance and precipitation variance contribute proportionally. Distance between cities is Euclidean. We filter out cities within 2° latitude/longitude (~140 miles) so that "twins" mean climatically similar but geographically distinct — not just the neighboring town. Full methodology →