Last updated: May 3, 2025
Understanding the UV Index is essential for residents of Karaj, Iran, as it plays a crucial role in sun safety and skin health. With the region's Csa climate, which brings dry summers and varied sunshine, knowing the daily UV levels can help prevent sunburn, reduce the risk of skin cancer, and promote overall skin well-being. The intensity of UV radiation in Karaj peaks dramatically during midday hours, reaching values as high as 12—indicating a very high risk for harm from unprotected sun exposure. Being informed about these levels can empower you to enjoy the outdoors while taking the necessary precautions for your skin's safety.
At 07:00, the UV Index starts at a modest 1, indicating low exposure risk. As the sun rises higher in the sky, the intensity escalates, reaching 3 by 08:00 and 6 by 09:00. The peak arrives at 12:00, with the index soaring to a maximum of 12, denoting a very high risk of harm from unprotected sun exposure. It remains intense through 13:00, before gradually tapering off—slipping to 11 at 14:00 and then decreasing further to 8 by 15:00. As the day winds down, the UV Index declines to 5 at 16:00 and continues its descent to 3 by 17:00, eventually resettling at a low 1 by 18:00 and lingering there until 19:00. This clear pattern underscores the importance of sun protection during peak hours, especially between 10:00 and 14:00 when the UV exposure is at its highest.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 3 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 12 | extreme | 10 min |
| 14:00 | 11 | extreme | 10 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 1 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The UV Index varies significantly throughout the year, showing distinct seasonal changes in sun exposure risk. January and February have a moderate UV Index of 4 and 5, allowing for about 30 minutes of sun exposure without burning. As we move into March and April, the UV Index climbs sharply to 8 and 9, categorized as very high, with burn times decreasing to 15 minutes. The peak of sun intensity occurs in May and June, where an extreme UV Index of 12 warrants a 10-minute exposure limit to prevent skin damage. July sees a slight decrease to 11, while August and September remain high at 10. In October, the risk lowers to a high index of 7, allowing for 25 minutes of safe exposure. Finally, November and December return to moderate levels of 4 and 3, with safer burn times of 30 minutes. Residents and visitors should take extra precautions during the high-risk months of March through September, utilizing sunscreen, protective clothing, and seeking shade during peak hours.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Karaj | 4 | 5 | 8 | 9 | 12 | 12 | 11 | 10 | 10 | 7 | 4 | 3 |
| Mashhad UVI | 4 | 5 | 8 | 10 | 12 | 12 | 12 | 11 | 10 | 7 | 4 | 3 |
| Tehran UVI | 4 | 6 | 8 | 9 | 13 | 12 | 11 | 10 | 10 | 7 | 5 | 3 |
| Tabriz UVI | 4 | 5 | 9 | 10 | 12 | 12 | 12 | 11 | 9 | 7 | 4 | 3 |
| Isfahan UVI | 5 | 7 | 10 | 10 | 13 | 13 | 12 | 11 | 10 | 9 | 6 | 4 |