Climate twins of Alton, MO
These are the US cities whose 12-month climate pattern most closely matches Alton'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: Alton vs its climate twin
Top match: Walnut Hill, IL
| Month | Alton | Walnut Hill | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 43.8°F | 22.4°F | 2.96 in | 38.8°F | 20.9°F | 2.87 in |
| February | 48.6°F | 25.1°F | 3.39 in | 44.0°F | 24.3°F | 2.58 in |
| March | 58.3°F | 33.7°F | 4.45 in | 54.2°F | 33.0°F | 3.90 in |
| April | 68.7°F | 43.2°F | 4.66 in | 66.2°F | 43.6°F | 4.81 in |
| May | 75.8°F | 53.1°F | 5.57 in | 75.2°F | 53.5°F | 5.20 in |
| June | 85.0°F | 61.7°F | 3.31 in | 84.1°F | 62.3°F | 4.08 in |
| July | 88.3°F | 65.9°F | 4.01 in | 87.5°F | 65.8°F | 3.85 in |
| August | 88.1°F | 64.2°F | 3.92 in | 86.9°F | 63.7°F | 3.54 in |
| September | 80.8°F | 55.4°F | 3.46 in | 81.0°F | 55.8°F | 3.29 in |
| October | 70.2°F | 42.8°F | 3.77 in | 69.3°F | 44.7°F | 3.45 in |
| November | 56.7°F | 33.2°F | 4.44 in | 54.9°F | 34.2°F | 4.09 in |
| December | 45.9°F | 25.7°F | 3.29 in | 43.2°F | 25.5°F | 3.02 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 →