UV Index in Hiroo, Japan

Last updated: May 3, 2025

In Hiroo, Japan, being aware of the UV Index is essential for maintaining skin health and preventing sunburn. As UV radiation levels can reach a peak of 9 around noon, understanding these fluctuations can help residents and visitors alike make informed decisions about sun protection. Hiroo, characterized by its Dfb climate, presents a unique blend of seasonal variations that influence UV exposure risks throughout the year. By staying vigilant and informed about the UV Index, you can enjoy the beautiful outdoors while safeguarding your skin from harmful effects.

Hourly UV Index in Hiroo

The UV Index rises steadily throughout the morning, peaking at 9 between 11:00 and 12:00, indicating a high level of solar radiation and necessitating precautionary measures for sun exposure. As the sun begins to lower, the index gradually declines, dropping to 7 at 1:00 PM before tapering off to 4 by 3:00 PM. Later in the afternoon, the UVI falls further to 2 at 4:00 PM, and finally stabilizes at 1 from 5:00 PM onwards, ensuring a safe environment as daylight fades. Overall, it's a day where sunscreen and protective clothing are essential during 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	3	moderate	30 min
08:00	5	moderate	30 min
09:00	6	high	25 min
10:00	8	very high	15 min
11:00	9	very high	15 min
12:00	9	very high	15 min
13:00	7	high	25 min
14:00	6	high	25 min
15:00	4	moderate	30 min
16:00	2	low	45 min
17:00	1	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Hiroo

Throughout the year, the UV Index experiences significant seasonal variations, with the highest risk months typically spanning from March to September. During this period, particularly in April, May, June, July, and August, the UV Index reaches a peak of 10, indicating a very high exposure category and a burn time of just 15 minutes. Conversely, the months of January and December signify the lowest UV levels, with an index of 2 and a burn time of 45 minutes. Visitors and residents should take caution during the high-risk months, employing protective measures such as sunscreen, hats, and sunglasses when spending time outdoors, as even short exposure can lead to skin damage. Being vigilant about UV levels can help ensure safety while enjoying the sun.

Monthly Maximum UV Index for Hiroo, Japan

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

The table above highlights how UV exposure in Hiroo 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.

Hiroo'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
Hiroo	2	3	6	8	9	10	10	10	8	6	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