UV Index in Iiyama, Japan

Last updated: May 3, 2025

Understanding the UV Index is crucial for residents and visitors in Iiyama, Japan, especially as the region experiences significant UV exposure. With peak values reaching up to 11 during midday, being aware of the UV levels can help you take essential precautions against sunburn and long-term skin damage. Iiyama's Dfb climate offers a unique blend of cold winters and warm summers, making it vital to recognize the risks associated with sun exposure throughout the year. By keeping an eye on the UV Index, you can protect your skin while enjoying the beautiful outdoors that Iiyama has to offer.

Hourly UV Index in Iiyama

The UV Index (UVI) exhibits a notable pattern throughout the day. Starting at 2 at 7:00 AM, it gradually rises, peaking at 11 by noon and 1:00 PM. This high level of UV exposure indicates that sun protection is essential during these hours. As the afternoon progresses, the UVI begins to dip, dropping to 7 by 2:00 PM and then declining further to 5 by 3:00 PM. By late afternoon, the sunlight's intensity reduces significantly, with the UVI falling to 1 by 5:00 PM and remaining minimal through 6:00 PM and 7:00 PM. This data underscores the importance of taking precautions during peak hours while enjoying the 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	2	low	45 min
08:00	4	moderate	30 min
09:00	7	high	25 min
10:00	9	very high	15 min
11:00	11	extreme	10 min
12:00	11	extreme	10 min
13:00	10	very high	15 min
14:00	7	high	25 min
15:00	5	moderate	30 min
16:00	3	moderate	30 min
17:00	1	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Iiyama

Throughout the year, UV radiation levels fluctuate significantly, impacting exposure risks for visitors and residents. The high-risk months for UV exposure are March through August, where the UV Index reaches very high to extreme levels, particularly peaking at an Index of 11 during May to August, allowing for a burn time of just 10 minutes. In contrast, the moderate UV conditions in January, November, and December allow for longer burn times of 30 minutes but still require caution. Visitors and residents should take appropriate precautions, such as wearing sunscreen, protective clothing, and sunglasses, especially during high UV months, to minimize the risk of skin damage.

Monthly Maximum UV Index for Iiyama, Japan

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

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

Iiyama's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sapporo UVI	2	3	6	7	9	9	9	10	8	5	3	2
Yokohama UVI	3	5	8	9	11	11	11	11	10	7	5	4
Tokyo UVI	3	5	8	9	11	11	11	11	10	7	5	4
Iiyama	4	6	9	9	11	11	11	11	10	7	5	3
Nagoya UVI	4	6	8	10	11	11	11	11	10	7	5	3
Osaka UVI	4	6	8	11	11	11	12	11	10	7	5	3