Climate twins of Mount Vernon, IL

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

Top match: Edgar Springs, MO

Month Mount Vernon Edgar Springs
High Low Precip High Low Precip
January 38.5°F 21.7°F 2.60 in 42.5°F 21.0°F 2.58 in
February 43.6°F 25.0°F 2.62 in 47.4°F 24.4°F 2.75 in
March 53.6°F 33.8°F 4.00 in 57.9°F 32.0°F 3.88 in
April 64.9°F 44.1°F 4.96 in 67.8°F 42.2°F 4.71 in
May 73.8°F 55.0°F 5.06 in 75.4°F 50.9°F 5.31 in
June 82.4°F 63.7°F 4.84 in 82.8°F 59.9°F 4.14 in
July 85.7°F 67.3°F 3.78 in 87.4°F 63.1°F 3.68 in
August 84.8°F 64.8°F 3.33 in 86.4°F 61.0°F 3.64 in
September 78.6°F 56.7°F 3.37 in 79.5°F 52.7°F 3.36 in
October 67.5°F 44.7°F 3.53 in 69.2°F 41.6°F 3.45 in
November 53.7°F 34.2°F 3.99 in 56.1°F 32.5°F 3.95 in
December 42.9°F 26.1°F 2.89 in 45.5°F 24.2°F 2.56 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 →