Climate twins of Seneca, IL

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

Top match: Roseville, IL

Month Seneca Roseville
High Low Precip High Low Precip
January 31.4°F 14.2°F 1.95 in 30.8°F 13.0°F 1.83 in
February 35.4°F 17.2°F 1.90 in 35.5°F 16.6°F 1.84 in
March 47.5°F 27.2°F 2.54 in 48.4°F 26.3°F 2.38 in
April 61.2°F 37.3°F 3.59 in 61.8°F 37.0°F 3.62 in
May 72.6°F 48.5°F 4.70 in 72.3°F 49.1°F 4.95 in
June 81.1°F 58.1°F 4.92 in 80.5°F 59.0°F 4.38 in
July 84.0°F 61.9°F 3.85 in 83.7°F 62.3°F 4.23 in
August 82.4°F 60.5°F 4.09 in 82.3°F 59.8°F 3.67 in
September 77.1°F 52.9°F 3.46 in 76.8°F 51.0°F 3.65 in
October 64.1°F 41.2°F 3.20 in 64.2°F 39.8°F 2.85 in
November 49.1°F 30.0°F 2.72 in 49.4°F 28.5°F 2.37 in
December 36.6°F 20.5°F 2.11 in 36.4°F 19.5°F 1.86 in

Cities that consider Seneca their climate twin

These US cities have Seneca in their top 3 most-similar list — meaning if you were to move from any of these places, Seneca 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 →