Climate twins of Sullivan, IL

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: Pearl, IL

Month Sullivan Pearl
High Low Precip High Low Precip
January 35.3°F 18.5°F 2.41 in 35.4°F 18.4°F 2.06 in
February 40.2°F 21.9°F 2.23 in 40.5°F 21.9°F 2.05 in
March 51.2°F 31.1°F 2.83 in 51.7°F 31.5°F 2.91 in
April 64.7°F 41.9°F 4.48 in 64.1°F 41.9°F 4.41 in
May 74.6°F 53.4°F 4.98 in 73.9°F 53.2°F 4.81 in
June 83.2°F 62.7°F 4.95 in 82.5°F 62.3°F 4.67 in
July 86.0°F 65.2°F 4.35 in 85.6°F 65.7°F 3.87 in
August 85.1°F 62.3°F 3.16 in 84.4°F 63.6°F 3.35 in
September 80.1°F 54.6°F 2.71 in 78.9°F 55.1°F 2.99 in
October 67.3°F 43.9°F 3.30 in 66.8°F 43.4°F 3.02 in
November 52.1°F 33.0°F 3.45 in 52.3°F 32.6°F 3.11 in
December 40.3°F 24.5°F 2.75 in 40.5°F 23.7°F 2.33 in

Cities that consider Sullivan their climate twin

These US cities have Sullivan in their top 3 most-similar list — meaning if you were to move from any of these places, Sullivan would feel familiar.

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 →