Ko Samet, Thailand: vitamin D, best months and travel guide
Small island with soft white sand, a short trip from Bangkok. Best for: weekenders, couples, families.
The best months for vitamin D in Ko Samet are November to April, when a full dose takes about 6 minutes at midday. Rainy or stormy from May to October.
Ko Samet month by month
| Month | Rating | Sun window | Peak UV | Full dose, age 30 | Afternoon high | Rainy days |
|---|---|---|---|---|---|---|
| January | Excellent | 7.2 h | 7.3 | 7 min | 32°C | 6/30 |
| February | Excellent | 8.1 h | 8.1 | 7 min | 31°C | 6/30 |
| March | Excellent | 8.4 h | 8.6 | 6 min | 31°C | 15/30 |
| April | Excellent | 8.7 h | 9.0 | 6 min | 33°C | 6/30 |
| May | Bad weather | 7.8 h | 8.0 | 7 min | 32°C | 20/30 |
| June | Bad weather | 6.5 h | 6.9 | 8 min | 30°C | 22/30 |
| July | Bad weather | 4.8 h | 5.2 | 10 min | 29°C | 29/30 |
| August | Bad weather | 7.9 h | 7.9 | 7 min | 30°C | 25/30 |
| September | Bad weather | 6.3 h | 6.6 | 8 min | 29°C | 25/30 |
| October | Bad weather | 6.8 h | 7.3 | 7 min | 30°C | 26/30 |
| November | Excellent | 7.3 h | 7.3 | 7 min | 31°C | 9/30 |
| December | Excellent | 6.9 h | 6.8 | 8 min | 30°C | 2/30 |
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 Ko Samet
Small island with soft white sand, a short trip from Bangkok. A hot dry season from November to February on both coasts, and monsoon rain from May to October on the Andaman side (Phuket, Krabi). The Gulf side (Samui) is driest in the first months of the year. March to May is very hot.
In Ko Samet afternoon highs average from 29°C in July to 33°C in April. The wettest month is July (about 29 rainy days out of 30) and the driest is December (2). Midday UV peaks at 9.0 in April, which is very strong, so protect your skin.
The nearest island beach escape from Bangkok (Wikivoyage, CC BY-SA 4.0)
More about Thailand · Thailand in April · Best places in April
Questions about Ko Samet
When is the best time to visit Ko Samet for vitamin D?
The best months for vitamin D in Ko Samet are November to April, when a full dose takes about 6 minutes at midday.
What is the weather like in Ko Samet?
Afternoon highs average from 29°C in July to 33°C in April. The wettest month is July, with about 29 rainy days out of 30.
Which months should I avoid in Ko Samet?
For a beach stay, avoid the months when it is rainy or stormy from May to October.