Climate twins of Perth, ND
These are the US cities whose 12-month climate pattern most closely matches Perth'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: Perth vs its climate twin
Top match: Mohall, ND
| Month | Perth | Mohall | ||||
|---|---|---|---|---|---|---|
| High | Low | Precip | High | Low | Precip | |
| January | 15.2°F | -3.4°F | 0.37 in | 16.4°F | -1.7°F | 0.43 in |
| February | 18.6°F | 0.0°F | 0.43 in | 20.6°F | 1.0°F | 0.47 in |
| March | 30.0°F | 11.5°F | 0.70 in | 32.9°F | 12.9°F | 0.73 in |
| April | 47.6°F | 24.9°F | 1.09 in | 51.2°F | 26.1°F | 1.13 in |
| May | 61.8°F | 38.0°F | 2.86 in | 64.8°F | 38.4°F | 2.51 in |
| June | 70.2°F | 49.3°F | 3.73 in | 73.9°F | 49.6°F | 3.76 in |
| July | 74.6°F | 54.1°F | 3.33 in | 79.1°F | 54.0°F | 2.62 in |
| August | 74.7°F | 51.7°F | 2.72 in | 79.6°F | 51.3°F | 2.24 in |
| September | 65.1°F | 42.6°F | 1.74 in | 69.2°F | 41.9°F | 1.70 in |
| October | 50.0°F | 29.4°F | 1.21 in | 52.8°F | 29.6°F | 1.33 in |
| November | 32.6°F | 15.6°F | 0.79 in | 34.5°F | 16.1°F | 0.75 in |
| December | 19.6°F | 2.9°F | 0.67 in | 21.1°F | 4.0°F | 0.55 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 →