Climate twins of Harrisburg, IL
These are the US cities whose 12-month climate pattern most closely matches Harrisburg'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: Harrisburg vs its climate twin
Top match: Ghent, KY
| Month | Harrisburg | Ghent | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 42.9°F | 24.0°F | 3.79 in | 41.3°F | 25.4°F | 3.61 in |
| February | 47.7°F | 28.3°F | 3.13 in | 46.1°F | 27.7°F | 3.01 in |
| March | 58.1°F | 36.1°F | 4.90 in | 56.6°F | 35.0°F | 4.42 in |
| April | 69.4°F | 45.7°F | 5.26 in | 69.1°F | 44.5°F | 4.54 in |
| May | 78.2°F | 56.5°F | 4.31 in | 77.8°F | 55.1°F | 4.94 in |
| June | 86.0°F | 65.1°F | 4.92 in | 84.6°F | 63.1°F | 5.18 in |
| July | 89.1°F | 68.4°F | 3.49 in | 88.5°F | 67.1°F | 4.21 in |
| August | 88.2°F | 65.6°F | 3.58 in | 87.6°F | 65.8°F | 3.79 in |
| September | 82.4°F | 57.3°F | 3.10 in | 81.4°F | 58.6°F | 3.31 in |
| October | 71.2°F | 45.4°F | 3.76 in | 69.4°F | 46.6°F | 3.42 in |
| November | 57.4°F | 36.3°F | 3.97 in | 55.9°F | 36.3°F | 3.85 in |
| December | 46.8°F | 28.9°F | 3.38 in | 44.9°F | 29.9°F | 4.20 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 →