UV Index in Longmont, United States

Last updated: May 3, 2025

Understanding the UV Index is crucial for residents and visitors of Longmont, Colorado, as it directly impacts skin health and sunburn prevention. With a climate classified as BSk, Longmont experiences significant UV exposure, particularly during peak hours when the index can soar to 11. By staying informed about daily UV levels, you can better protect yourself and your family from harmful rays, ensuring that outdoor activities remain enjoyable and safe. Remember, knowledge is your best defense against skin damage!

Hourly UV Index in Longmont

The UV Index steadily climbs as the day progresses, starting from a mild 1 at 7:00 AM and reaching a peak of 11 by 1:00 PM. Sun-seekers and outdoor enthusiasts should be mindful, as the index hits a high of 10 at 12:00 PM, signaling significant UV exposure. After this peak, the index gradually decreases, dropping to 8 by 3:00 PM, and continuing to decline to 1 by 7:00 PM. For safe sun enjoyment, it’s best to take precautions during those high UV hours, particularly between 11:00 AM and 2:00 PM. Remember to sport your hats and sunscreen!

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	4	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	6	high	25 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Longmont

Throughout the year, UV levels exhibit significant seasonal variations, with high-risk months occurring from March to August, when the UV Index consistently reaches very high to extreme levels. April and May display peak values of 11, while June and July escalate to 12, indicating a critical need for sun protection during these times. Visitors and residents should exercise caution, especially during peak sunlight hours, by wearing protective clothing, applying broad-spectrum sunscreen, and seeking shade to minimize the risk of skin damage. As autumn approaches, the UV Index gradually decreases, returning to moderate levels in November and December, providing a more comfortable sun exposure environment.

Monthly Maximum UV Index for Longmont, United States

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

The table above highlights how UV exposure in Longmont 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.

Longmont'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
Longmont	4	6	8	11	11	12	12	11	9	6	4	3
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5