Ishigaki, Japan: vitamin D, best months and travel guide
Gateway island to the Yaeyama group, with snorkelling and manta rays. Best for: divers, couples.
The best months for vitamin D in Ishigaki are February, March, when a full dose takes about 8 minutes at midday. Too cool from December to January and rainy or stormy from April to November.
Ishigaki month by month
| Month | Rating | Sun window | Peak UV | Full dose, age 30 | Afternoon high | Rainy days |
|---|---|---|---|---|---|---|
| January | Too cold | 4.1 h | 4.4 | 12 min | 21°C | 11/30 |
| February | Good | 5.3 h | 5.5 | 10 min | 23°C | 14/30 |
| March | Good | 6.4 h | 6.6 | 8 min | 23°C | 15/30 |
| April | Bad weather | 8.3 h | 8.4 | 6 min | 27°C | 25/30 |
| May | Bad weather | 7.4 h | 7.5 | 7 min | 28°C | 25/30 |
| June | Bad weather | 8.8 h | 8.3 | 6 min | 30°C | 25/30 |
| July | Bad weather | 8.5 h | 8.3 | 6 min | 31°C | 23/30 |
| August | Bad weather | 8.3 h | 8.2 | 7 min | 31°C | 23/30 |
| September | Bad weather | 8.0 h | 8.0 | 7 min | 30°C | 24/30 |
| October | Bad weather | 6.3 h | 6.3 | 8 min | 29°C | 25/30 |
| November | Bad weather | 4.0 h | 4.5 | 12 min | 26°C | 20/30 |
| December | Too cold | 2.1 h | 3.1 | 17 min | 22°C | 16/30 |
Sun window is the number of hours a day with UV Index 2.5 or higher. Full dose is the minutes at midday for about 1,000 IU of vitamin D with a quarter of the body bare, for skin type III. Rainy days are days with at least 1 mm out of 30.
What to expect in Ishigaki
Gateway island to the Yaeyama group, with snorkelling and manta rays. A hot, humid summer with typhoon risk from July to October, and mild winters that are too cool for swimming. The swimming season is April to October. English is limited outside the big hotels.
In Ishigaki afternoon highs average from 21°C in January to 31°C in July. The wettest month is April (about 25 rainy days out of 30) and the driest is January (11). Midday UV peaks at 8.4 in April, which is very strong, so protect your skin.
Questions about Ishigaki
When is the best time to visit Ishigaki for vitamin D?
The best months for vitamin D in Ishigaki are February, March, when a full dose takes about 8 minutes at midday.
What is the weather like in Ishigaki?
Afternoon highs average from 21°C in January to 31°C in July. The wettest month is April, with about 25 rainy days out of 30.
Which months should I avoid in Ishigaki?
For a beach stay, avoid the months when it is too cool from December to January and rainy or stormy from April to November.