September weather forecast
Yosemite National Park, CA

September witnesses a moderate decline in temperatures in Yosemite National Park, paving the way for the autumn season. Receiving an average of 0.7" (18mm) of rainfall, the weather conditions remain relatively dry. With daylight reducing to 12.4 hours and 10 hours of sunshine, the environment vibrantly transforms. The cool weather complements the changing foliage; leaves turn into variegated shades of yellow, gold, and red. The park's ground is strewn with fall leaves, creating a colorful carpet that enchants every visitor.

Temperature

September in Yosemite National Park heralds a minor drop in average high-temperature, sliding from August's hot 89.4°F (31.9°C) to a warm 83.5°F (28.6°C). The month of September sees a significant daily temperature drop, recording an average low-temperature of 46.8°F (8.2°C) in Yosemite National Park, California.

Rainfall

In September, in Yosemite National Park, California, the rain falls for 2 days. Throughout September, 0.67" (17mm) of precipitation is accumulated. Throughout the year, in Yosemite National Park, there are 65 rainfall days, and 36.26" (921mm) of precipitation is accumulated.

Snowfall

In Yosemite National Park, snow does not fall in June through September.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:28 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:53 am and sunset at 6:42 pm PDT.

Sunshine

In Yosemite National Park, California, the average sunshine in September is 10h.

UV index

In Yosemite National Park, the average daily maximum UV index in September is 8. A UV Index reading of 8 to 10 represents a very high health hazard from unsafe exposure to UV radiation for average individuals.
Note: In September, the maximum UV index of 8 suggests this advice:
Take extra precautions. Protection against sun damage is required. Avoid exposure to the Sun and try to stay in the shade between 10 a.m. and 4 p.m., when UV radiation is most potent, but be aware that parasols or canopies may not offer full protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.