Climate twins of Romeoville, IL
These are the US cities whose 12-month climate pattern most closely matches Romeoville'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: Romeoville vs its climate twin
Top match: Hillsdale, IL
| Month | Romeoville | Hillsdale | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 31.7°F | 16.1°F | 2.19 in | 30.8°F | 14.6°F | 1.64 in |
| February | 36.3°F | 19.7°F | 1.98 in | 35.7°F | 18.6°F | 1.81 in |
| March | 48.5°F | 29.7°F | 2.71 in | 48.9°F | 29.3°F | 2.70 in |
| April | 61.0°F | 39.6°F | 4.11 in | 62.2°F | 39.9°F | 3.96 in |
| May | 72.4°F | 50.3°F | 4.81 in | 73.7°F | 51.6°F | 4.87 in |
| June | 81.5°F | 60.3°F | 4.68 in | 82.8°F | 61.5°F | 4.42 in |
| July | 84.7°F | 64.5°F | 4.50 in | 85.7°F | 65.1°F | 4.13 in |
| August | 82.7°F | 63.0°F | 4.36 in | 83.4°F | 62.9°F | 4.10 in |
| September | 76.4°F | 55.4°F | 3.31 in | 77.1°F | 54.5°F | 3.57 in |
| October | 63.8°F | 43.5°F | 3.67 in | 64.0°F | 42.9°F | 3.21 in |
| November | 48.9°F | 31.9°F | 2.67 in | 48.8°F | 30.7°F | 2.56 in |
| December | 36.8°F | 22.0°F | 2.15 in | 35.9°F | 20.5°F | 2.12 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 →