UV Index in Heidelberg, United States

Last updated: August 1, 2025

In Heidelberg, United States, staying informed about the UV Index is crucial for protecting your skin and overall health. Understanding UV levels not only aids in sunburn prevention but also helps in maintaining long-term skin health. With a humid subtropical climate (Cfa), residents face varied UV exposure risks, especially during peak sunlight hours when the UV Index can reach as high as 11 around midday. By being mindful of these levels, you can enjoy the outdoors safely while minimizing the potential for skin damage.

Hourly UV Index in Heidelberg

Expect a sunny day with a fluctuating UV Index that peaks at 11 around midday. The morning starts off gentle, with values rising from 1 at 7:00 AM to 4 by 9:00 AM. As the sun climbs higher, the UV Index escalates sharply, reaching 9 by 11:00 AM and hitting its highest point of 11 at both 12:00 PM and 1:00 PM. After the sun’s zenith, the UV levels gradually decline, dropping to 10 at 2:00 PM and tapering off to 1 by 7:00 PM. Remember to protect your skin during those peak hours for a safe and enjoyable day outdoors!

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	9	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	5	moderate	30 min
17:00	3	moderate	30 min
18:00	1	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Heidelberg

Throughout the year, the UV Index displays notable seasonal fluctuations, particularly increasing from January to August. The highest risk occurs during the spring and summer months, with April through August recording an extreme UV Index of 11, necessitating a burn time as short as 10 minutes. March and September follow closely with very high indices of 8 and 10, respectively. Hence, visitors and residents are advised to take precautions during February to October, particularly in the peak summer months. Sunscreen application, protective clothing, and seeking shade during peak hours are essential for minimizing harmful UV exposure and preventing sunburn. In contrast, the winter months of January, November, and December see lower UV levels, offering a respite, albeit still warranting moderate protection.

Monthly Maximum UV Index for Heidelberg, United States

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

The table above highlights how UV exposure in Heidelberg 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.

Heidelberg'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
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Heidelberg	4	7	8	11	11	11	11	11	10	8	6	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5