UV index in San Francisco today
Live UV level in San Francisco, California right now, today's hourly forecast, and how long until your skin type burns.
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| Hour | UV index | Level |
|---|
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When is UV highest in San Francisco?
UV peaks around solar noon — roughly 12–2pm local time. Seasonally, UV in San Francisco peaks May through September. In that peak period, summer UV in San Francisco typically peaks in the high to very high range (6–9) around midday.
In December and January, UV in San Francisco usually stays in the low range, and sunburn risk is minimal outside of snow-reflection or high-altitude situations.
Typical midday peak UV by month
| Month | Typical peak | Level |
|---|---|---|
| January | 2.9 | Low |
| February | 3.9 | Moderate |
| March | 5.5 | Moderate |
| April | 6.9 | High |
| May | 7.9 | High |
| June | 8.2 | Very high |
| July | 8.1 | Very high |
| August | 7.5 | High |
| September | 6.4 | High |
| October | 5 | Moderate |
| November | 3.3 | Moderate |
| December | 2.7 | Low |
Mean of daily peak UV, 2024–2025 model data. Click a month for detail on burn times and what to pack.
Do I need sunscreen in San Francisco today?
Use the live reading above: the protection threshold is UV 3. If any part of your time outdoors falls in the hours marked moderate or higher, wear SPF 30+ broad-spectrum sunscreen and reapply every two hours. Water, sand, and snow reflect UV and can push your effective exposure well above the forecast number — as does altitude, at roughly +10% per 1,000 m.