UV Index in Johnston, United States

Last updated: May 3, 2025

Understanding the UV Index in Johnston, United States, is crucial for protecting your skin from harmful ultraviolet rays. As UV levels fluctuate throughout the day, being aware of these changes can help in preventing sunburn and safeguarding overall skin health. Johnston's Dfa climate often experiences intense UV exposure, particularly during midday hours when the index peaks at 9, posing a higher risk for sun-related damage. Stay informed and take proactive measures to enjoy the outdoors safely!

Hourly UV Index in Johnston

The UV Index for the day showcases a notable rise in intensity as the sun climbs higher in the sky. Starting at a low of 1 at 7:00 AM, the index gradually increases to a moderate level of 3 by 9:00 AM. However, from 10:00 AM onward, things heat up significantly, peaking at a scorching 9 from noon to 2:00 PM. As the afternoon progresses, the UV Index gradually dips back to a friendly 3 by 5:00 PM, then descends further to 1 by the time evening sets in. This pattern underscores the importance of sun protection during peak hours, especially between 11:00 AM and 2:00 PM, when UV levels are at their highest.

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	5	moderate	30 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	9	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Johnston

Throughout the year, UV Index levels fluctuate significantly, impacting sun exposure and potential skin damage. The high-risk months, identified by an increased UV Index, are April through August, where levels reach a concerning 8 to 11, categorized as either very high to extreme. Notably, June exhibits the peak UV Index of 11, necessitating vigilant sun protection. Residents and visitors are advised to minimize sun exposure during these months, seeking shade and applying broad-spectrum sunscreen regularly, especially during peak hours. In contrast, winter months like January, November, and December present a moderate risk with an UV Index of 3 to 4, allowing for more lenient outdoor activities while still practicing sun safety.

Monthly Maximum UV Index for Johnston, United States

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

The table above highlights how UV exposure in Johnston 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.

Johnston'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
Johnston	3	5	6	8	9	11	10	9	8	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