San Francisco UV index in September
Typical ultraviolet levels for San Francisco during September, from the past year of data.
Very High
San Francisco
Very high UV. Limit sun exposure, especially during midday; protective clothing, sunscreen, and a hat are essential.
8.2
UV Index
September average UTC
Low
Moderate
High
Very High
Extreme
September UV
8.1625
Risk level
Very High
Yearly peak
10.8042
Peak month
July
San Francisco UV index — monthly trend
Average UV index by month over the past year, with September highlighted.
Visiting San Francisco in September?
In September, San Francisco's typical UV index is about 8.1625 — a very high risk level. Very high UV. Limit sun exposure, especially during midday; protective clothing, sunscreen, and a hat are essential.
Across the year, San Francisco sees the strongest UV in Summer, peaking around 10.8042 in July. Plan sun protection accordingly.
