Vitamin D in Vietnam in December: sun, UV and what to expect
Bad weather Bad weather: it rains on about 21 days in December (rainy or monsoon season), so sun is hard to count on and a beach stay is not recommended.
5.0 hsun window (UV 2.5+)
5.4peak UV Index
10 minto a full dose
27°Cafternoon high
21/30rainy days
19/30sunny days
The country rating is for a typical beach, but some places in Vietnam still work in December: Phú Quốc (excellent), Ho Chi Minh City (good), Côn Đảo (good), Mũi Né (good).
How long in the sun in December?
- If you travel anyway, 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 Nha Trang, 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 Vietnam in December
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Phú Quốc | Excellent | 7.0 h | 8 min | 30°C | 12/30 |
| Ho Chi Minh City | Good | 5.9 h | 9 min | 30°C | 13/30 |
| Côn Đảo | Good | 5.8 h | 9 min | 26°C | 16/30 |
| Mũi Né | Good | 5.5 h | 9 min | 30°C | 11/30 |
| Hanoi | Fair | 3.0 h | 15 min | 22°C | 3/30 |
| Nha Trang | Bad weather | 5.0 h | 10 min | 27°C | 21/30 |
| Hạ Long Bay | Too cold | 4.3 h | 12 min | 21°C | 5/30 |
| Da Nang | Bad weather | 2.9 h | 16 min | 25°C | 25/30 |
| Huế | Bad weather | 2.2 h | 18 min | 24°C | 27/30 |
| Hoi An | Bad weather | 2.1 h | 19 min | 24°C | 28/30 |
Other months in Vietnam
- Jan Good
- Feb Excellent
- Mar Excellent
- Apr Excellent
- May Too hot
- Jun Too hot
- Jul Too hot
- Aug Too hot
- Sep Bad weather
- Oct Bad weather
- Nov Bad weather
- Dec Bad weather
Best months: January to April. Full Vietnam guide