Naha, Japan: vitamin D, best months and travel guide
Okinawa's capital of markets, a castle and easy access. Best for: city-break fans, foodies.
The best months for vitamin D in Naha are May, October, November, when a full dose takes about 8 minutes at midday. Too cool from December to March and rainy or stormy in April and from June to September.
Naha month by month
| Month | Rating | Sun window | Peak UV | Full dose, age 30 | Afternoon high | Rainy days |
|---|---|---|---|---|---|---|
| January | Too cold | 4.1 h | 4.3 | 12 min | 20°C | 6/30 |
| February | Too cold | 5.1 h | 5.1 | 10 min | 21°C | 11/30 |
| March | Too cold | 6.1 h | 6.6 | 8 min | 22°C | 15/30 |
| April | Bad weather | 7.3 h | 7.5 | 7 min | 25°C | 18/30 |
| May | Excellent | 7.1 h | 7.1 | 8 min | 26°C | 16/30 |
| June | Bad weather | 6.7 h | 6.9 | 8 min | 29°C | 20/30 |
| July | Bad weather | 8.6 h | 8.2 | 7 min | 32°C | 21/30 |
| August | Bad weather | 7.8 h | 7.7 | 7 min | 31°C | 21/30 |
| September | Bad weather | 7.7 h | 7.5 | 7 min | 31°C | 23/30 |
| October | Good | 6.8 h | 6.4 | 8 min | 29°C | 14/30 |
| November | Good | 5.1 h | 4.9 | 11 min | 25°C | 11/30 |
| December | Too cold | 2.9 h | 3.5 | 15 min | 21°C | 12/30 |
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 Naha
Okinawa's capital of markets, a castle and easy access. 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 Naha afternoon highs average from 20°C in January to 32°C in July. The wettest month is September (about 23 rainy days out of 30) and the driest is January (6). Midday UV peaks at 8.2 in July, which is very strong, so protect your skin.
Questions about Naha
When is the best time to visit Naha for vitamin D?
The best months for vitamin D in Naha are May, October, November, when a full dose takes about 8 minutes at midday.
What is the weather like in Naha?
Afternoon highs average from 20°C in January to 32°C in July. The wettest month is September, with about 23 rainy days out of 30.
Which months should I avoid in Naha?
For a beach stay, avoid the months when it is too cool from December to March and rainy or stormy in April and from June to September.