Last updated: July 2, 2025
Understanding the UV Index in Jamestown, located within the unique climate of Saint Helena, Ascension, and Tristan da Cunha, is crucial for safeguarding your skin health. With UV levels peaking at 8 between noon and 1 PM, the risk of sunburn is noticeably elevated during those hours. Awareness of the UV Index empowers residents and visitors alike to make informed decisions about sun protection, minimizing the risks of skin damage. Given Jamestown's BWh climate, where sunny days are common, being mindful of UV exposure is essential for enjoying the outdoors while keeping your skin safe. Don’t let the sun catch you off guard—stay informed and protect yourself effectively!
At dawn, the UV Index remains low, peaking at 1 by 08:00. As the sun rises higher, a notable increase occurs, reaching 3 at 09:00 and escalating dramatically to a maximum of 8 from 12:00 to 13:00. This midday surge indicates a higher risk for sun exposure, making it essential to take precautions such as wearing sunscreen and protective clothing. The intensity then gradually declines, dropping to 4 by 15:00, and continuing its descent to 0 by 19:00, marking the end of the sun’s peak influence for the day. Stay mindful of these hourly fluctuations to enjoy the sun safely!
| 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 | 8 | very high | 15 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 |