UV Index in San Mateo, California
Monday
07/21
Current UV Index:
10.27
Risk of dangerous harm
A UV Index of 11 or higher means an extremely high risk of harm from unprotected sun exposure. Take every precaution as unprotected skin and eyes can burn in minutes.
UV Index Scale
0
- 2
Low risk of harm
A UV index of 0 to 2 means that the danger from the Sun's UV rays to the average person is low.
3
- 5
Medium risk of harm
A UV index of 3 to 5 means a moderate risk of harm from unprotected sun exposure.
6
- 7
High risk of harm
A UV Index of 6 to 7 means a high risk of harm from unprotected sun exposure. Skin and eye protection is essential.
8
- 10
Very high risk of harm
A UV Index of 8 to 10 means there is a very high risk of harm from unprotected sun exposure. Take extra precautions as unprotected skin and eyes are vulnerable and can burn quickly.
11+
Risk of dangerous harm
A UV Index of 11 or higher means an extremely high risk of harm from unprotected sun exposure. Take every precaution as unprotected skin and eyes can burn in minutes.
Hourly UV Index Forecast
Wear sunglasses on sunny days. In winter, reflection can double the intensity of UV rays.
If you burn easily, cover up and use sunscreen.
If you burn easily, cover up and use sunscreen.
1-2
Low
3-5
Medium
6-7
High
8-10
Very high
11+
Extremely high
Daily UV Index Forecast
Today
07/21
15o
/
20o
10.27
Risk of dangerous harm
Tue
07/22
13o
/
19o
8.38
Very high risk of harm
Wed
07/23
13o
/
20o
9.51
Very high risk of harm
Thu
07/24
13o
/
20o
9.69
Very high risk of harm
Fri
07/25
13o
/
19o
9.94
Very high risk of harm
Sat
07/26
12o
/
19o
10
Very high risk of harm
Sun
07/27
13o
/
20o
10
Very high risk of harm
Mon
07/28
13o
/
22o
10
Very high risk of harm
07/21/2025
19o
Broken clouds
15oC
/
20oC
| Real feel
19oC
0% rain
|
0 mm
13
0
5.0
07/21/2025
14
0
5.0
07/21/2025
56
0
5.0
07/16/2025
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