UV Index in San Francisco, Mexico

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents and visitors in San Francisco, Mexico, where sun exposure can lead to skin damage and health risks. The UV levels here can fluctuate significantly throughout the day, peaking at a dangerous level of 13 between noon and 2 PM, making sunburn prevention essential. With San Francisco's unique Cwa climate, characterized by dry summers and relatively mild winters, it’s important to stay informed about your UV exposure to protect your skin and maintain overall health. Whether you're enjoying the coastline or exploring the vibrant city, knowing the UV Index can help you make safer choices under the sun.

Hourly UV Index in San Francisco

The UV Index throughout the day reveals a striking pattern of increased solar intensity. Starting off at a mild 1 at 07:00 and 08:00, the risk begins to rise steadily, reaching a moderate 3 by 09:00. As the sun climbs higher, the index hits 5 at 10:00, escalating to a peak of 13 between 13:00 and 14:00—a point where caution is advised for outdoor activities. Fortunately, as the day transitions towards evening, the UV levels start to decline, dropping to 8 at 16:00 and further down to 1 by 19:00. This data emphasizes the need for sun protection during the midday hours, especially when the UV Index surges to its highest levels.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	1	low	45 min
09:00	3	moderate	30 min
10:00	5	moderate	30 min
11:00	8	very high	15 min
12:00	11	extreme	10 min
13:00	13	extreme	10 min
14:00	13	extreme	10 min
15:00	11	extreme	10 min
16:00	8	very high	15 min
17:00	5	moderate	30 min
18:00	3	moderate	30 min
19:00	1	low	45 min

Monthly UV Index Trends in San Francisco

The UV index experiences significant seasonal variation, peaking during the spring and summer months. January and February show a very high UV Index of 8 and 10, respectively, with a burn time of just 15 minutes. However, from March through October, the indices reach extreme levels, peaking at 14 in April and July, where the burn time drops to just 10 minutes. High-risk months for UV exposure are March to October, making it essential for visitors and residents to take precautions, such as wearing protective clothing, using sunscreen, and seeking shade during peak hours. As we move into November and December, the UV Index decreases, though exposure risks remain; November is still very high at 9, while December sees a high index of 7 with a longer burn time of 25 minutes. Thus, vigilance is advised year-round, particularly from late winter to early autumn.

Monthly Maximum UV Index for San Francisco, Mexico

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in San Francisco. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for San Francisco, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare San Francisco UV Index with Other Mexico Cities

The table above highlights how UV exposure in San Francisco compares to other major locations across Mexico. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

San Francisco's solar exposure compared to other cities in Mexico. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
San Francisco	8	10	13	14	13	13	14	13	13	11	9	7
Guadalajara UVI	9	11	14	14	14	13	13	13	13	12	9	8
Iztapalapa UVI	10	12	14	15	14	14	14	14	14	12	10	8
Ecatepec de Morelos UVI	10	12	14	15	15	14	14	13	14	12	10	8
Mexico City UVI	10	12	14	15	15	14	14	13	14	12	10	8
Puebla UVI	10	12	14	15	15	15	15	14	14	13	10	9