UV Index in Umi, Japan

Last updated: May 3, 2025

Understanding the UV Index in Umi, Japan is crucial for maintaining optimal skin health and preventing sunburn. With a Cfa climate that brings warm summers and mild winters, residents and visitors alike must be vigilant about UV exposure, particularly during peak hours. On sunny days, the UV Index can soar to 11 at noon, making it essential to protect your skin to avoid long-term damage. By staying informed about daily UV levels, you can enjoy the beautiful outdoors safely and wisely.

Hourly UV Index in Umi

The UV Index today follows a dynamic trajectory, peaking dramatically as the sun climbs. Starting at a modest 1 at 07:00, it rises to 3 by 08:00 and then continues its ascent, reaching 5 by 09:00. The intensity escalates further, peaking at an impressive 11 at 12:00—a time when sun protection is crucial. As the afternoon wears on, the index moderately descends, dropping to 10 by 13:00 and gradually decreasing to 6 at 15:00. By 16:00, it falls to 4, before tapering off to 1 by 18:00 and remaining constant until 19:00. This hourly breakdown highlights the importance of being sun-smart during peak hours, especially when the index is at its 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	3	moderate	30 min
09:00	5	moderate	30 min
10:00	8	very high	15 min
11:00	10	very high	15 min
12:00	11	extreme	10 min
13:00	10	very high	15 min
14:00	9	very high	15 min
15:00	6	high	25 min
16:00	4	moderate	30 min
17:00	2	low	45 min
18:00	1	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Umi

Throughout the year, seasonal changes in UV exposure highlight periods of heightened risk for residents and visitors. From January to February, the UV Index rises from 4 (moderate) to 6 (high), reducing safe exposure time to 25 minutes. Significant increases occur in March, reaching 8 (very high), and peaking during the summer months of April to August at 11-12 (extreme), where only 10 minutes of unprotected exposure is advisable. The risk, while still present, decreases again in September and returns to high levels in October and November with a UV Index of 6-7, allowing for 25 minutes of safe exposure. As such, it is crucial for visitors and residents to remain vigilant, especially during the summer, taking precautions like wearing sunscreen, protective clothing, and seeking shade during peak hours to mitigate the risk of UV-related health issues.

Monthly Maximum UV Index for Umi, Japan

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

The table above highlights how UV exposure in Umi 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.

Umi'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
Umi	4	6	8	11	11	11	12	12	11	7	6	4