Last updated: June 2, 2025
In Hanno, Japan, where the climate is classified as Cfa, being aware of the UV Index is crucial for protecting your skin and overall health. Understanding UV levels helps residents and visitors alike to take the necessary precautions against sunburn and long-term skin damage. With UV Index values peaking at 11 during midday hours, it's essential to stay informed about the risks associated with high UV exposure. Knowing when to seek shade or wear protective gear can significantly reduce the chances of harmful effects, ensuring you enjoy the beautiful outdoor spaces that Hanno has to offer while keeping your skin safe.
As the day unfolds, the UV Index rises sharply, peaking during the midday hours. At 07:00, it begins at a modest 2, but by 09:00, it escalates to 7, urging outdoor enthusiasts to take precautions. The sun reaches its zenith between 10:00 and 12:00, with the index soaring to a maximum of 11—a clear signal for sun safety measures. As the afternoon progresses, the intensity diminishes; by 14:00, it drops to 7, and further declines to 5 by 15:00. As daylight wanes, the index continues to fall, resting at 1 by 17:00 and tapering off to 0 post 19:00. This rhythmic rise and fall of UV exposure highlights the importance of midday vigilance against harmful rays.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 5 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 10 | 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 | 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 |
Throughout the year, seasonal changes in UV Index reveal significant variations in sun exposure risk. The high-risk months for UV exposure are predominantly from March to August, with the peak occurring in May, June, July, and August, where the UV Index reaches 11, categorized as extreme with a burn time of just 10 minutes. During this period, individuals are strongly advised to take precautions such as wearing sunscreen, protective clothing, and seeking shade, especially between 10 AM and 4 PM, when UV radiation is at its strongest. In contrast, the UV Index indicates moderate levels in January, November, and December, and high levels in October and February—months where sun safety should still be observed, though the urgency is somewhat reduced.
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 |
| Hanno | 4 | 6 | 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 |