Vitamin D in Tonga in September: sun, UV and what to expect
Excellent Excellent. The sun is strong for most of the day in Tonga in September, so a full vitamin D dose takes only about 7 minutes at midday, and the usable window lasts 7.0 hours a day.
7.0 hsun window (UV 2.5+)
7.4peak UV Index
7 minto a full dose
24°Cafternoon high
15/30rainy days
27/30sunny days
Best places in Tonga in September: Neiafu (excellent), Haʻapai (excellent), Nukuʻalofa (excellent), Tongatapu (excellent), ʻEua (excellent).
How long in the sun in September?
- Plan your sun session around midday (roughly 11:00 to 15:00), when the UV Index peaks at about 7.4. With about a quarter of your skin bare, a full dose takes around 7 minutes for skin type III at age 30, and about 14 minutes at age 65.
- Stop well before your skin turns pink. At this UV level skin type III can start to burn after about 27 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 8.1, which is very strong. Keep sessions short and protect the rest of the day.
- 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 | 5 min | 9 min | 18 min |
| Type II | 6 min | 11 min | 23 min |
| Type III | 7 min | 14 min | 27 min |
| Type IV | 11 min | 20 min | 41 min |
| Type V | 14 min | 27 min | 54 min |
| Type VI | 24 min | 45 min | 90 min |
Minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, at Nukuʻalofa, 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 September
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Neiafu | Excellent | 7.4 h | 7 min | 25°C | 7/30 |
| Haʻapai | Excellent | 7.2 h | 7 min | 24°C | 5/30 |
| Nukuʻalofa | Excellent | 7.0 h | 7 min | 24°C | 15/30 |
| Tongatapu | Excellent | 6.9 h | 7 min | 24°C | 15/30 |
| ʻEua | Excellent | 6.9 h | 8 min | 23°C | 17/30 |
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