Climate twins of Helena, MT

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

Top match: Fromberg, MT

Month	Helena			Fromberg
	High	Low	Precip	High	Low	Precip
January	32.4°F	13.5°F	0.39 in	35.4°F	12.9°F	0.29 in
February	37.2°F	17.2°F	0.42 in	38.9°F	15.1°F	0.33 in
March	47.5°F	24.6°F	0.52 in	50.4°F	22.4°F	0.47 in
April	56.7°F	32.4°F	1.02 in	57.7°F	29.9°F	1.57 in
May	66.4°F	41.5°F	1.95 in	67.4°F	39.6°F	2.25 in
June	74.7°F	48.7°F	2.21 in	77.3°F	47.0°F	1.80 in
July	86.1°F	55.1°F	1.06 in	87.2°F	53.1°F	0.83 in
August	84.6°F	52.9°F	1.04 in	86.3°F	50.2°F	0.61 in
September	73.3°F	44.6°F	0.96 in	75.3°F	41.5°F	1.15 in
October	57.6°F	33.5°F	0.78 in	59.7°F	31.7°F	1.23 in
November	42.8°F	22.8°F	0.59 in	45.8°F	22.2°F	0.60 in
December	32.6°F	14.2°F	0.46 in	35.9°F	14.2°F	0.37 in

Cities that consider Helena their climate twin

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

Harlem, MT (ranks Helena #1)

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 →