Vitamin D in U.S. Virgin Islands in July: sun, UV and what to expect
Excellent Excellent. The sun is strong for most of the day in U.S. Virgin Islands in July, so a full vitamin D dose takes only about 6 minutes at midday, and the usable window lasts 8.7 hours a day.
Best places in U.S. Virgin Islands in July: Cruz Bay (excellent), Trunk Bay (excellent), Charlotte Amalie (excellent), Magens Bay (excellent).
Open U.S. Virgin Islands for July on the map Find stays in U.S. Virgin Islands
How long in the sun in July?
- Plan your sun session around midday (roughly 11:00 to 15:00), when the UV Index peaks at about 8.7. With about a quarter of your skin bare, a full dose takes around 6 minutes for skin type III at age 30, and about 11 minutes at age 65.
- Stop well before your skin turns pink. At this UV level skin type III can start to burn after about 23 minutes of midday sun, so cover up, find shade and use SPF 30+ on skin that stays out.
- On clear days the UV Index reaches about 9.1, which is very strong. Keep sessions short and protect the rest of the day.
- Storm season: July is within the tropical storm season here. Storms are possible but less likely than at the peak, so check forecasts and use flexible bookings and travel insurance.
- Water, sand and light surfaces reflect UV, so at the beach you get a little more sun than the number suggests, for the good and the bad.
| Skin type | Full dose, age 30 | Full dose, age 65 | Time to burn |
|---|---|---|---|
| Type I | 4 min | 8 min | 15 min |
| Type II | 5 min | 10 min | 19 min |
| Type III | 6 min | 11 min | 23 min |
| Type IV | 9 min | 17 min | 34 min |
| Type V | 12 min | 23 min | 46 min |
| Type VI | 20 min | 38 min | 77 min |
Minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, at Charlotte Amalie, the median coastal place. Time to burn is the time to reach one minimal erythemal dose and does not depend on age. A rough planning guide, not medical advice.
Places in U.S. Virgin Islands in July
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Cruz Bay | Excellent | 8.9 h | 6 min | 29°C | 16/30 |
| Trunk Bay | Excellent | 8.9 h | 6 min | 29°C | 16/30 |
| Charlotte Amalie | Excellent | 8.7 h | 6 min | 29°C | 16/30 |
| Magens Bay | Excellent | 8.7 h | 6 min | 29°C | 16/30 |
| Christiansted | Bad weather | 8.8 h | 6 min | 31°C | 18/30 |
Other months in U.S. Virgin Islands
- Jan Excellent
- Feb Excellent
- Mar Excellent
- Apr Bad weather
- May Bad weather
- Jun Excellent
- Jul Excellent
- Aug Bad weather
- Sep Bad weather
- Oct Excellent
- Nov Bad weather
- Dec Good
Best months: June, July, October, December to March. Full U.S. Virgin Islands guide