Glacier National Park in March

July through September is prime time, but each month brings trade-offs. July means wildflowers exploding across alpine meadows, but also peak crowds and $400-per-night hotel rates in nearby Whitefish. August offers the most reliable weather — warm days, cool nights, and all high-elevation trails finally snow-free. But this is also when every family in America decides to visit. September is the sweet spot: fewer crowds, golden aspen trees, and elk bugling season. Just know that snow can hit the high country any time after Labor Day. June is tricky — the Going-to-the-Sun Road usually doesn't fully open until late in the month due to snow removal. Many high-elevation trails stay buried under 10 feet of snow well into July. Winter visits are possible but require serious preparation; only the first few miles of park roads stay plowed, and temperatures regularly hit -20°F.