Last updated: June 2, 2025
Understanding the UV Index in Jamestown, Saint Helena, Ascension, and Tristan da Cunha is crucial for protecting your skin and maintaining your overall health. With maximum UV levels peaking at an index of 8 during midday, awareness of these fluctuations can significantly aid in sunburn prevention and lower your risk of long-term skin damage. Given Jamestown's BWh climate characterized by sunny, dry conditions, it's essential to be mindful of UV exposure, especially during the late morning and early afternoon hours. Stay informed and enjoy the beautiful outdoors while keeping your skin safe!
As the day breaks, the UV Index gradually rises, peaking at a robust 8 at 12:00 PM, signaling the sun's intensity is at its highest. Starting from a mild 1 at 07:00 AM and 08:00 AM, the UV levels steadily climb, hitting 5 by 10:00 AM. By 11:00 AM, a brisk 7 indicates that sun safety measures are essential. The intensity slightly declines after noon, tapering off to 6 at 2:00 PM, and then gradually decreases to a 4 by 3:00 PM. By evening, the UV Index drops back to a mere 1 at 5:00 PM and ultimately falls to 0 after 6:00 PM, signaling a safe return home as the sun sets. Keep this UV pattern in mind for outdoor activities to protect your skin and enjoy the day!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 7 | high | 25 min |
| 14:00 | 6 | high | 25 min |
| 15:00 | 4 | moderate | 30 min |
| 16:00 | 2 | low | 45 min |
| 17:00 | 1 | low | 45 min |
| 18:00 | 0 | low | 45 min |
| 19:00 | 0 | low | 45 min |
Throughout the year, UV Index levels display significant seasonal variations, with extreme levels persisting from January to April and again in September to November. The highest UV Index is recorded in the first four months of the year, peaking at 15, necessitating a cautious approach with a burn time of only 10 minutes. As temperatures rise, the UV Index decreases slightly in May and June, yet still maintains a very high category, allowing for a burn time of 15 minutes. The late summer months, particularly August, report slightly elevated levels before dropping again in the fall. Visitors and residents should take special care during high-risk months, particularly from January to April and September to November, by using appropriate sun protection strategies such as sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize sun exposure and risk of skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Edinburgh of the Seven Seas UVI | 14 | 13 | 11 | 7 | 4 | 3 | 3 | 5 | 8 | 10 | 12 | 15 |
| Jamestown | 15 | 15 | 13 | 12 | 9 | 8 | 8 | 10 | 11 | 14 | 14 | 15 |
| Longwood UVI | 15 | 15 | 13 | 12 | 9 | 8 | 8 | 10 | 11 | 14 | 14 | 15 |
| Half Tree Hollow UVI | 15 | 15 | 13 | 12 | 9 | 8 | 8 | 10 | 11 | 14 | 14 | 15 |
| Georgetown UVI | 14 | 14 | 14 | 13 | 12 | 10 | 10 | 11 | 12 | 13 | 14 | 14 |