Last updated: August 1, 2025
Understanding the UV Index in Yokohama, Japan is essential for protecting your skin and overall health. With the city's climate classified as Dfb, residents and visitors must be aware of UV levels that can reach as high as 10 during midday hours. This heightened exposure increases the risk of sunburn and long-term skin damage. By being informed about the UV Index, you can take proactive measures to enjoy the beautiful Yokohama outdoors while keeping your skin safe. Whether you're exploring the vibrant city or soaking up the sun at the beach, knowing the UV Index will empower you to make smarter choices regarding sun protection.
The UV Index throughout the day displayed a notable rise, peaking at 10 between 11:00 AM and 12:00 PM, indicating a high risk of harm from unprotected sun exposure. Early risers experienced a moderate index, starting at 3 at 7:00 AM, while the intensity escalated significantly to 8 by 10:00 AM. A gradual decline followed after noon, with the index falling back to 5 by 3:00 PM, and dropping further to 1 by 5:00 PM, signaling a gentle evening. As the day progressed into the night, the UV Index settled at 0 by 7:00 PM, wrapping up a day of fluctuating sun exposure risks. Always remember to protect your skin during the peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | 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 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 min |
| 15:00 | 5 | moderate | 30 min |
| 16:00 | 3 | moderate | 30 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 0 | low | 45 min |
The UV Index varies significantly throughout the year, reflecting seasonal changes in sun exposure. High-risk months for UV radiation include late spring and summer, specifically from April to August, when levels reach very high to extreme ratings, making burn times as low as 10 to 15 minutes. Visitors and residents should be particularly vigilant during these months; protective measures, such as wearing sunscreen, hats, and sunglasses, are essential. January through March and October exhibit moderate to high UV levels, where burn times range from 25 to 30 minutes, while November and December present lower UV risks with longer burn times of 30 to 45 minutes. It’s advisable to monitor local UV forecasts and adjust outdoor activities accordingly to minimize skin damage.
UV Risk Categories
| 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 | 3 | 4 | 5 | 8 | 9 | 10 | 10 | 11 | 8 | 6 | 4 | 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 |