Last updated: May 3, 2025
Understanding the UV Index is crucial for residents and visitors in Hatsukaichi, Japan, where the Cfa climate brings warm summers and increased sun exposure. Being aware of UV levels helps to prevent sunburn and promote long-term skin health, as the risk of harmful effects rises significantly during peak hours. With UV Index values reaching a high of 11 around noon, it's essential to stay informed and take protective measures, especially given the area's typical sunny conditions. Whether you're enjoying the stunning views of the Seto Inland Sea or exploring the lush landscapes, knowing the UV Index can help you make safer choices for your outdoor activities.
At dawn, the UV Index starts off gently at 2 by 7:00 AM, gradually rising as the sun climbs higher in the sky. By 09:00 AM, it reaches a moderate 6, but the real intensity hits at 11:00 AM and 12:00 PM, peaking at 11—a stark reminder to stay protected from the sun's rays. As the afternoon rolls on, the index begins to taper off, dropping to 8 at 2:00 PM, then declining further to 6 by 3:00 PM. As the day winds down, the UV Index falls to a safe 1 by 6:00 PM, signaling a welcome reprieve from the sun's powerful influence. Always remember to take precautions during those peak hours!
| 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 | 8 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 8 | 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 | 1 | low | 45 min |
Throughout the year, UV Index levels exhibit significant seasonal variation, with the highest risks occurring in the spring and summer months. From March to August, the UV Index reaches extreme levels, peaking at 12 in July and August, where the recommended burn time is just 10 minutes. The months of April and May also maintain an extreme UV Index of 11. Conversely, during January and December, UV exposure is at a moderate level with a UV Index of 4, allowing for a burn time of 30 minutes. For residents and visitors, it is crucial to be particularly cautious from March through September, taking protective measures like wearing sunscreen, protective clothing, and limiting sun exposure during peak hours. Remain vigilant and prioritize skin safety, especially during the high-risk months of April through August.
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 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 |
| Hatsukaichi | 4 | 5 | 8 | 11 | 11 | 11 | 12 | 12 | 10 | 7 | 6 | 4 |