Weather in Yosemite during September

September mornings in Yosemite arrive crisp at around 4.3°C (40°F), but the days warm to a pleasant 17.7°C (64°F)—cool enough to hike all day without overheating, warm enough to ditch the heavy jacket by midday. Rainfall drops to just 20.2mm across the month, spread thinly over roughly 4.6 rainy days, so you'll see far more blue sky than cloud. With 11.7 hours of daily sunshine, the light cuts clean and sharp across granite cliffs, and the air holds that dry, crystalline quality that makes Yosemite's granite glow. Evening temperatures can dip quickly, so layers matter.

The valley feels noticeably quieter in September than summer—families have returned to school routines, and the relentless tourist traffic of July and August thins out significantly. Campgrounds are easier to book, trails feel spacious, and ranger-led programs continue without the crowds. Local hikers and photographers flock here specifically for this window: the light is softer than August's harsh noon glare, wildflowers still dot meadows, and waterfalls still flow (though reduced from spring). Prices on lodging and activities ease downward, making it one of the better value months to visit.

Over the past decade, September has remained consistently dry and mild—2026 conditions align closely with the historical norm, with no significant warming or cooling trend that would reshape the month's character. September has become even more popular with savvy travelers as climate patterns shift and peak-season heat makes July and August less comfortable, but it hasn't yet reached the saturation of those months.

This month suits active travelers who want real hiking without altitude or extreme heat, photographers chasing golden-hour light on stone, families with school-age kids squeezing in one final trip before fall, and anyone seeking Yosemite without the summer throngs. In 2026, plan on layering, bringing a light rain jacket just in case, and booking accommodations several weeks ahead—September fills faster each year.