Climate twins of Letcher, SD
These are the US cities whose 12-month climate pattern most closely matches Letcher'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: Letcher vs its climate twin
Top match: Pierre, SD
| Month | Letcher | Pierre | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 28.6°F | 9.3°F | 0.40 in | 29.0°F | 9.3°F | 0.45 in |
| February | 32.7°F | 13.4°F | 0.37 in | 33.7°F | 12.6°F | 0.74 in |
| March | 45.4°F | 24.3°F | 0.93 in | 45.7°F | 22.9°F | 0.96 in |
| April | 58.7°F | 35.1°F | 2.07 in | 58.5°F | 33.3°F | 1.93 in |
| May | 70.8°F | 47.8°F | 3.15 in | 69.5°F | 44.9°F | 3.25 in |
| June | 81.2°F | 58.5°F | 3.51 in | 80.0°F | 55.6°F | 3.69 in |
| July | 86.7°F | 63.9°F | 2.36 in | 88.3°F | 61.6°F | 2.39 in |
| August | 83.9°F | 60.5°F | 3.14 in | 86.6°F | 59.4°F | 1.95 in |
| September | 76.8°F | 51.0°F | 2.34 in | 77.5°F | 49.7°F | 1.74 in |
| October | 61.7°F | 37.8°F | 1.83 in | 60.7°F | 36.2°F | 1.69 in |
| November | 45.6°F | 24.2°F | 0.55 in | 44.9°F | 23.2°F | 0.77 in |
| December | 31.9°F | 14.1°F | 0.49 in | 32.4°F | 13.2°F | 0.64 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 →