Central Idaho in March

June through September offers your best shot at accessible roads and decent weather. But even summer nights drop into the 40s at elevation. July and August bring crowds to places like Redfish Lake, but venture 10 miles off the main highway and you'll have trails to yourself. September delivers stunning fall colors and fewer people, but some high-elevation passes start closing by mid-month. Spring comes late — snow lingers on mountain passes through May. Winter transforms Central Idaho into a different planet entirely. Cross-country skiing and snowmobiling work if you're prepared for serious cold, but most lodges and services shut down. The shoulder seasons of May and October offer deals but unpredictable weather. Check road conditions religiously; Highway 21 and the Sawtooth Scenic Byway close without warning when storms hit.