Last updated: August 1, 2025
Understanding the UV Index is crucial for residents of Altdorf, Germany and visitors alike, as it serves as a vital tool for safeguarding your skin from harmful ultraviolet rays. Awareness of UV levels is essential, especially in a climate zone like Cfb, where typical summer days can escalate UV exposure risks significantly. With UV Index values peaking at a striking 8 during midday, it's important to recognize that even short periods of unprotected sun exposure can lead to sunburn and long-term skin health issues. Staying informed about UV conditions can help you take appropriate precautions, ensuring that your time outdoors remains enjoyable and safe.
The hourly UV Index data reveals a fascinating story of sun exposure throughout the day. Starting at 1 at 07:00, the index steadily climbs to 8 by 12:00, reaching its peak intensity during the peak sun hours from 12:00 to 14:00. Here, the UV levels maintain a high 8, urging sun lovers to take precautions against harmful rays. As the afternoon transitions into the evening, the index gradually declines, tapering off to 4 by 17:00, and finally sinking back to 1 by 19:00. This data makes it clear: the sun's reach is strongest mid-day, and mindful sun safety is essential for those enjoying outdoor activities during these hours.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 4 | moderate | 30 min |
| 11:00 | 6 | high | 25 min |
| 12:00 | 7 | high | 25 min |
| 13:00 | 7 | high | 25 min |
| 14:00 | 7 | high | 25 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits significant seasonal variations, with the highest levels occurring from May to July, categorized as very high with a burn time of just 15 minutes. April marks the transition into higher UV exposure, registering a UV Index of 6 and a high exposure category. Conversely, the winter months of January, November, and December remain in the low exposure category, with burn times up to 45 minutes. Visitors and residents should be particularly cautious during the high-risk months of May, June, and July, when it is crucial to seek shade, wear protective clothing, and apply sunscreen regularly to minimize the risk of skin damage. As the UV Index decreases in the fall and winter, vigilance can be relaxed, but some level of sun protection remains advisable year-round.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hamburg UVI | 1 | 2 | 3 | 5 | 7 | 8 | 7 | 7 | 5 | 3 | 2 | 1 |
| Berlin UVI | 1 | 2 | 4 | 5 | 7 | 8 | 7 | 7 | 5 | 3 | 2 | 1 |
| Koeln UVI | 1 | 2 | 4 | 5 | 7 | 8 | 8 | 7 | 5 | 4 | 2 | 1 |
| Frankfurt am Main UVI | 2 | 3 | 4 | 5 | 8 | 8 | 8 | 7 | 5 | 4 | 2 | 1 |
| Altdorf | 2 | 3 | 5 | 6 | 8 | 8 | 8 | 7 | 6 | 4 | 2 | 1 |
| Munich UVI | 2 | 3 | 5 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 1 |