Climate twins of Sullivan, WI

These are the US cities whose 12-month climate pattern most closely matches Sullivan'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: Sullivan vs its climate twin

Top match: Zwingle, IA

Month Sullivan Zwingle
High Low Precip High Low Precip
January 26.9°F 11.3°F 1.68 in 26.5°F 11.1°F 1.32 in
February 31.0°F 14.1°F 1.78 in 30.9°F 15.0°F 1.57 in
March 43.2°F 23.9°F 2.13 in 44.1°F 26.3°F 2.25 in
April 56.4°F 34.7°F 3.85 in 57.7°F 37.2°F 4.06 in
May 68.5°F 46.0°F 4.25 in 69.2°F 48.5°F 4.30 in
June 78.3°F 56.1°F 4.90 in 78.5°F 58.6°F 5.19 in
July 82.1°F 60.1°F 4.11 in 81.5°F 62.0°F 4.80 in
August 80.3°F 58.6°F 3.97 in 79.6°F 60.0°F 3.95 in
September 73.3°F 50.8°F 3.47 in 72.9°F 51.8°F 3.82 in
October 60.0°F 39.5°F 2.95 in 59.9°F 39.9°F 2.93 in
November 45.0°F 27.9°F 2.35 in 44.8°F 28.1°F 2.21 in
December 32.5°F 17.4°F 2.08 in 31.8°F 17.2°F 1.80 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 →