UV Index in Iiyama, Japan

Last updated: June 2, 2025

Being aware of the UV Index is crucial for residents and visitors of Iiyama, Japan. Understanding UV levels can help you take vital steps to prevent sunburn and protect your skin health, especially during the peak hours when the index is at its highest, peaking at 11 around midday. The Dfb climate of Iiyama typically offers a mix of warm summers and cold winters, but during the summer months, the risk of UV exposure increases significantly. By staying informed about daily UV conditions, you can enjoy the outdoors safely while keeping your skin protected from harmful rays.

Hourly UV Index in Iiyama

The UV Index showcases an intense midday sun, peaking at 11 between 11:00 AM and 12:00 PM. As the day progresses, the UV levels rise quickly; from a mild 2 at 07:00 AM, they soar to 9 by 10:00 AM, reflecting an increasing urgency for sun protection. The midday hours are particularly critical, where skin can suffer damage after just 15 minutes of exposure. After 2:00 PM, there’s a gradual decline in UV intensity, dropping to 5 by 3:00 PM, then to a safer 2 by 5:00 PM, finally decreasing to 0 after 6:00 PM. This data emphasizes the importance of staying mindful of UV exposure, especially during the peak 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	2	low	45 min
08:00	5	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	8	very high	15 min
15:00	5	moderate	30 min
16:00	3	moderate	30 min
17:00	2	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