UV Index
UV Index
Today's UV index in San Francisco, United States 
will be up to 8.7, indicating a very high level of sun exposure for the average person. Check our tips for today to make sure you're safe in the sun.
Last checked: 2025-05-10
With a UV index of 8.7 in San Francisco, it's crucial to safeguard your skin from harmful UV rays. Protect yourself by minimizing sun exposure, wearing protective clothing, and applying SPF 30+ sunscreen every 2 hours.
San Francisco's UV index is typically low to moderate, often ranging from 1 to 6, with higher values in summer months. The city's coastal fog often reduces direct sunlight, keeping UV levels lower than inland areas.
The weather in San Francisco features mild, wet winters and cool, dry summers. Fog is common in summer, especially in the mornings, caused by the cold Pacific Ocean meeting warmer air. Rainfall mainly occurs from November through March.
Compared to other parts of California, San Francisco is cooler and less sunny. Neighboring cities like Oakland or San Jose have warmer summers and less fog. Its coastal location keeps temperatures stable, unlike inland areas with hot summers and cold winters.
See the UV index hour by hour for San Francisco, along with the temperature and how cloudy it is. If the UV level is higher than moderate, it's best to avoid direct sunlight.