Vitamin D in Hawaii in January: sun, UV and what to expect
Good Good. A full dose takes about 9 minutes at midday, and the usable window is about 6.2 hours a day.
6.2 hsun window (UV 2.5+)
5.8peak UV Index
9 minto a full dose
26°Cafternoon high
13/30rainy days
27/30sunny days
Best places in Hawaii in January: Kailua-Kona (good), Hilo (good), Lahaina (good), Kaanapali (good), Kihei (good).
How long in the sun in January?
- Plan your sun session around midday (roughly 11:00 to 15:00), when the UV Index peaks at about 5.8. With about a quarter of your skin bare, a full dose takes around 9 minutes for skin type III at age 30, and about 17 minutes at age 65.
- Stop well before your skin turns pink. At this UV level skin type III can start to burn after about 34 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 | 6 min | 11 min | 23 min |
| Type II | 8 min | 14 min | 29 min |
| Type III | 9 min | 17 min | 34 min |
| Type IV | 14 min | 26 min | 52 min |
| Type V | 18 min | 34 min | 69 min |
| Type VI | 31 min | 57 min | 1.9 h |
Minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, at Waikiki, 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 Hawaii in January
| Place | Rating | Sun window | Full dose | Afternoon high | Rainy days |
|---|---|---|---|---|---|
| Kailua-Kona | Good | 6.7 h | 8 min | 26°C | 10/30 |
| Hilo | Good | 6.4 h | 9 min | 26°C | 11/30 |
| Lahaina | Good | 6.7 h | 8 min | 26°C | 14/30 |
| Kaanapali | Good | 6.7 h | 8 min | 26°C | 14/30 |
| Kihei | Good | 6.1 h | 9 min | 26°C | 10/30 |
| Waikiki | Good | 6.2 h | 9 min | 26°C | 13/30 |
| Honolulu | Good | 6.2 h | 9 min | 26°C | 13/30 |
| Poipu | Good | 5.9 h | 9 min | 25°C | 13/30 |
| Hanalei | Good | 6.0 h | 10 min | 26°C | 15/30 |
| Hana | Bad weather | 6.2 h | 9 min | 25°C | 20/30 |
Other months in Hawaii
- Jan Good
- Feb Excellent
- Mar Excellent
- Apr Bad weather
- May Bad weather
- Jun Excellent
- Jul Excellent
- Aug Excellent
- Sep Excellent
- Oct Excellent
- Nov Good
- Dec Good
Best months: June to March. Full Hawaii guide