UV Index in Iyo, Japan

Last updated: May 3, 2025

Understanding the UV Index is crucial for residents and visitors in Iyo, Japan, where the climate can lead to heightened sun exposure risks. With peak UV levels often reaching as high as 12 around midday, awareness of UV ratings is vital for effective sunburn prevention and maintaining healthy skin. The Cfa climate of Iyo, characterized by warm summers, creates conditions where UV rays can be particularly intense. By monitoring the UV Index, you can enjoy the outdoors while safeguarding your skin against harmful effects.

Hourly UV Index in Iyo

The UV Index presents a striking profile throughout the day, peaking dramatically from 11:00 AM to 12:00 PM with a maximum value of 12, indicating an intense level of solar radiation. Early risers will notice a more moderate ascent as the index starts at 2 at 07:00 AM, gradually climbing to 3 by 08:00 AM. The real intensity begins at 09:00 AM, surging to 6 before reaching a zenith of 11 by 11:00 AM. As the sun begins to dip post-noon, the index recedes to 9 at 02:00 PM, then gently descends to 6 by 03:00 PM, and continues its downward trend to settle at 0 by 07:00 PM. This data emphasizes the importance of sun protection during the peak hours when ultraviolet radiation is most potent.

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	3	moderate	30 min
09:00	6	high	25 min
10:00	9	very high	15 min
11:00	11	extreme	10 min
12:00	12	extreme	10 min
13:00	11	extreme	10 min
14:00	9	very high	15 min
15:00	6	high	25 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 Iyo

The UV Index shows significant seasonal changes, with the highest levels of ultraviolet radiation occurring from March to September, characterized by very high to extreme exposure categories. March and April see UV Index values ranging from 9 to 10, while May through August peak at 12, indicating an extreme risk of harm from unprotected sun exposure, with a notably short burn time of just 10 minutes. July and August are particularly high-risk months, necessitating careful sun protection measures. As the months progress toward October, there is a decrease to 8, moving back to very high levels, while November and December return to high and moderate levels, respectively. To ensure safety, visitors and residents are strongly advised to adopt protective measures, such as using sunscreen, wearing protective clothing, and seeking shade during peak sun hours, particularly during the high-risk months of May through September.

Monthly Maximum UV Index for Iyo, Japan

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

The table above highlights how UV exposure in Iyo 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.

Iyo'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
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
Iyo	4	6	9	10	12	11	12	12	11	8	6	4