Climate twins of Philadelphia, PA
These are the US cities whose 12-month climate pattern most closely matches Philadelphia'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: Philadelphia vs its climate twin
Top match: Kittrell, NC
| Month | Philadelphia | Kittrell | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 41.6°F | 27.8°F | 3.61 in | 50.6°F | 25.8°F | 3.67 in |
| February | 44.9°F | 29.6°F | 3.34 in | 54.2°F | 27.1°F | 3.11 in |
| March | 53.5°F | 36.4°F | 4.54 in | 61.9°F | 33.8°F | 4.17 in |
| April | 65.9°F | 46.3°F | 4.00 in | 72.7°F | 42.5°F | 3.86 in |
| May | 75.7°F | 56.3°F | 4.06 in | 79.2°F | 53.4°F | 3.90 in |
| June | 84.9°F | 65.9°F | 4.77 in | 86.6°F | 62.1°F | 4.48 in |
| July | 89.3°F | 71.4°F | 4.75 in | 90.1°F | 66.7°F | 4.43 in |
| August | 87.2°F | 69.5°F | 4.95 in | 88.0°F | 64.9°F | 5.13 in |
| September | 80.3°F | 62.7°F | 4.88 in | 82.2°F | 58.4°F | 4.78 in |
| October | 68.1°F | 51.1°F | 4.15 in | 72.2°F | 45.3°F | 3.57 in |
| November | 56.4°F | 41.3°F | 3.37 in | 62.2°F | 34.4°F | 3.64 in |
| December | 46.5°F | 33.2°F | 4.27 in | 53.5°F | 28.8°F | 3.89 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 →