Vitamin D in Tonga in July: sun, UV and what to expect
Good Good. A full dose takes about 10 minutes at midday, and the usable window is about 5.8 hours a day.
5.8 hsun window (UV 2.5+)
5.4peak UV Index
10 minto a full dose
24°Cafternoon high
10/30rainy days
27/30sunny days
Best places in Tonga in July: Haʻapai (good), Nukuʻalofa (good), Tongatapu (good), ʻEua (good), Neiafu (good).
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 5.4. With about a quarter of your skin bare, a full dose takes around 10 minutes for skin type III at age 30, and about 19 minutes at age 65.
- Stop well before your skin turns pink. At this UV level skin type III can start to burn after about 37 minutes of midday sun, so cover up, find shade and use SPF 30+ on skin that stays out.
- 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 | 7 min | 12 min | 25 min |
| Type II | 8 min | 15 min | 31 min |
| Type III | 10 min | 19 min | 37 min |
| Type IV | 15 min | 28 min | 56 min |
| Type V | 20 min | 37 min | 74 min |
| Type VI | 33 min | 62 min | 2.1 h |
Minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, at Tongatapu, 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 Tonga in July
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Haʻapai | Good | 5.9 h | 10 min | 24°C | 5/30 |
| Nukuʻalofa | Good | 5.8 h | 10 min | 24°C | 10/30 |
| Tongatapu | Good | 5.8 h | 10 min | 24°C | 10/30 |
| ʻEua | Good | 5.8 h | 10 min | 23°C | 12/30 |
| Neiafu | Good | 5.4 h | 10 min | 25°C | 7/30 |
Other months in Tonga
- Jan Bad weather
- Feb Bad weather
- Mar Bad weather
- Apr Excellent
- May Bad weather
- Jun Good
- Jul Good
- Aug Good
- Sep Excellent
- Oct Bad weather
- Nov Bad weather
- Dec Bad weather
Best months: April, June to September. Full Tonga guide