UV Index in Yountville, United States

Last updated: July 2, 2025

In Yountville, United States, staying informed about the UV Index is essential for protecting your skin and preventing sunburn. Understanding UV levels helps residents and visitors alike make informed choices about outdoor activities, ensuring skin health throughout the year. With its Mediterranean climate characterized by warm, dry summers and mild, wet winters, Yountville experiences UV exposure that can reach a peak index of 11 by midday, emphasizing the need for vigilance during sun-filled days. Protect yourself and enjoy the beautiful weather by being aware of the UV Index!

Hourly UV Index in Yountville

As the sun rises, the UV Index starts off gently at 1 by 7:00 AM, gradually climbing as the day progresses. By 10:00 AM, it reaches 6, signaling a notable increase in solar radiation. The intensity peaks at 12:00 PM with a striking 10 and continues to soar to a maximum of 11 at 1:00 PM, marking the hour of greatest exposure. As the afternoon unfolds, the index begins to taper off—dropping to 10 at 2:00 PM and 8 by 3:00 PM. By late afternoon, the UV Index gracefully descends to 4 at 5:00 PM, settling back to 2 by 6:00 PM and finally returning to a gentle 1 by 7:00 PM. This highlights the importance of sun protection during mid-day when UV rays are at their most intense.

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	2	low	45 min
09:00	3	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	10	very high	15 min
13:00	11	extreme	10 min
14:00	10	very high	15 min
15:00	8	very high	15 min
16:00	6	high	25 min
17:00	4	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Yountville

Throughout the year, UV exposure varies significantly, with high-risk months typically occurring from March to September. During these months, particularly in April through July, the UV index reaches notably high levels, peaking at 11, which indicates extreme exposure risks and a quick burn time of just 10 minutes. As the seasons shift, visitors and residents should be particularly vigilant from May to August, when protective measures such as sunscreen, hats, and seeking shade are essential to prevent skin damage. In contrast, January, November, and December present a moderate UV index of 3-4, allowing for longer burn times of 30 minutes, though sunscreen should still be applied. Staying informed about these UV changes can help ensure safe outdoor activities year-round.

Monthly Maximum UV Index for Yountville, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Yountville. 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 Yountville, 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 Yountville UV Index with Other United States Cities

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

Yountville's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Chicago UVI	3	4	6	8	9	10	10	9	8	6	4	2
Brooklyn UVI	3	5	6	8	10	10	9	9	8	6	4	2
New York City UVI	3	5	6	8	10	10	9	9	8	6	4	2
Yountville	3	5	7	9	10	11	11	10	9	6	4	3
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5