UV Index in Joetsu, Japan

Last updated: June 2, 2025

Staying informed about the UV Index in Joetsu, Japan is crucial for protecting your skin and overall health. Understanding UV levels helps you prevent sunburn and reduces the risk of long-term skin damage, which is especially important under the region's Cfa climate, known for its humid, subtropical weather. With UV Index levels peaking at 11 during midday, Joetsu residents and visitors should be aware of the heightened exposure risks and take necessary precautions to enjoy the sun safely. Stay vigilant and embrace the sunny days while keeping your skin protected!

Hourly UV Index in Joetsu

The UV Index throughout the day presents a dynamic picture of sun exposure. As early as 7:00 AM, the index starts at a mild 2, ramping up to a moderate 4 by 8:00 AM. The sun's intensity peaks around 11:00 AM and 12:00 PM with a striking 11, marking the height of caution for outdoor activities. As we move into the afternoon, the index gradually declines, dropping to 8 by 2:00 PM and further to 5 by 3:00 PM. The evening brings relief, with the UV Index decreasing to a 1 by 5:00 PM and finally hitting 0 by 7:00 PM. It’s clear that the midday hours pose the greatest risk, so sun safety measures are essential during those peak times.

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.
TimeUVICategoryTime to Burn
07:002low45 min
08:004moderate30 min
09:007high25 min
10:009very high15 min
11:0011extreme10 min
12:0011extreme10 min
13:0010very high15 min
14:008very high15 min
15:005moderate30 min
16:003moderate30 min
17:001low45 min
18:001low45 min
19:000low45 min

Monthly UV Index Trends in Joetsu

The UV Index exhibits significant seasonal variation, peaking during the summer months. High-risk months, particularly from March to August, see the UV Index reach extremes, with levels of 8 to 11 categorized as very high to extreme, resulting in quick burn times ranging from 10 to 15 minutes. Visitors and residents should take precautions during these months by seeking shade, wearing protective clothing, and applying sunscreen to minimize sun exposure. The UV levels decrease from September to November, but caution is still advised, especially with a moderate UV Index in the cooler months. Stay informed and protect your skin to enjoy the outdoors safely year-round.

Monthly Maximum UV Index for Joetsu, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Joetsu. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec3589101111119653
Data source: Statistical UV Index data for Joetsu, 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 Joetsu UV Index with Other Japan Cities

The table above highlights how UV exposure in Joetsu 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.
Joetsu's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Sapporo UVI2367999108532
Joetsu3589101111119653
Yokohama UVI35891111111110754
Tokyo UVI35891111111110754
Nagoya UVI468101111111110753
Osaka UVI468111111121110753