Winter: desert and low elevation
Death Valley, Joshua Tree, Saguaro, and Grand Canyon South Rim are comfortable or accessible in winter when mountain parks are snowbound.
Everglades dry season draws birders but beats summer humidity. Many alpine roads close, which quiets Yellowstone and Glacier for a different trip type.
Spring: waterfalls and desert comfort
Utah red-rock parks and Joshua Tree shine before summer heat. Yosemite waterfalls peak in May with heavy crowds unless you go midweek.
High roads like Tioga and Going-to-the-Sun may still be closed. Spring break weekends spike desert parks.
Summer: big terrain and coast
Canyonlands, Capitol Reef, and Great Basin absorb crowds better than single-road parks. Olympic and Acadia offer cooler coastal options.
Famous valleys still need dawn arrivals. Timed entry is common at Arches, Rocky Mountain, and Yosemite in peak summer.
Fall: foliage tradeoffs
September weekdays at Grand Teton and Rocky Mountain beat July. October leaf weekends at Smokies and Shenandoah are among the year's busiest non-summer dates.
Desert parks cool into pleasant hiking weather with thinner crowds than spring.
Compare on the same dates
Use park forecast pages to compare Capitol Reef versus Zion on your exact week, not just the season name.