UV Index in Rialto, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Rialto, United States, where sunny days often invite outdoor activities but can also pose significant risks to skin health. As local UV levels can reach a peak of 12 during midday hours, it's essential to be aware of these fluctuations to prevent sunburn and long-term skin damage. With Rialto's Csa climate, featuring warm, dry summers, the potential for intense sun exposure is high. By staying informed about the UV Index, you can enjoy the beautiful weather while protecting your skin and ensuring your outdoor adventures remain safe and enjoyable.

Hourly UV Index in Rialto

From dawn until dusk, the UV Index showcases a dynamic shift throughout the day. At 7:00 AM, it starts at a mild level of 1, gradually inching higher with the sun's ascent. By 10:00 AM, the index reaches 7, indicating a noteworthy intensity. The peak is experienced at 12:00 PM and 1:00 PM, where it soars to a powerful 12, marking the need for protective measures. As afternoon transitions to evening, it gracefully descends—11 at 2:00 PM, 8 at 3:00 PM, and dwindling to 1 by 7:00 PM. This rollercoaster of UV exposure underscores the importance of sun safety during the most intense hours!

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	7	high	25 min
11:00	10	very high	15 min
12:00	12	extreme	10 min
13:00	12	extreme	10 min
14:00	11	extreme	10 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 Rialto

As we observe seasonal changes in the UV Index, it becomes clear that higher levels of ultraviolet radiation occur during the warmer months. The high-risk months peak from March to August, with May and June reaching extreme levels (UV Index 11-12) and burn times as low as 10 minutes. Visitors and residents are strongly advised to take precautions during these months by seeking shade, wearing protective clothing, and using sunscreen, especially between 10 AM and 4 PM when UV exposure is at its highest. January, November, and December are comparatively safer, with moderate UV levels (Index 4-5) and longer burn times of 30 minutes. Staying informed about the UV Index is essential for maintaining skin health year-round.

Monthly Maximum UV Index for Rialto, United States

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

The table above highlights how UV exposure in Rialto 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.

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