Montana is part of Great Plains
Every Great Plains region shares one system — the same maps, the same live radar, the same climate record. Montana is two states in one weather map. West of the Divide the Pacific gets in: Missoula and the Flathead run milder and wetter, and the valleys hold their inversions for weeks. East of it there is nothing between the Hi-Line and the Arctic, and Havre and Glasgow post some of the coldest readings in the lower 48. In between, the Rocky Mountain Front makes chinooks that have moved the thermometer 47 degrees in seven minutes at Loma — still the world record.