The official "High Season" on Thailand's West Coast lasts from November until April. However, during the month of November and December in might still be raining on some days.
Here is an overview over the general weather conditions troughout the year in Ao Nang:
Weather in Ao Nang by Month
- Ap Nang in January - March : mostly dry, no wind and waves on the beach, blue sky and sunny
- Ao Nang in April: By the middle of this month is the time when the monsoon wind changes direction. It starts raining and there will be waves at the beach.
- Ao Nang in May: Just like the second half of April: rainy and windy.
- Ao Nang in June - September: Mostly sunny but rain showers on some days. Sometimes cloudy and waves at the beach.
- Ao Nang in October By the middle of this month is the time when the monsoon wind will turn around once again. Weather will change very often during this time with long and heavy rain showers. However, during this time, the weather is still a lot better in Ao Nang than on Thailand's East Coast (Koh Samui, Koh Phangan and Koh Tao) where the hefty rain usually causes flooding and landslides.
- Ao Nang in November: Start of the High Season in Ao Nang but it might still be raining on some days until middle of December.
- Ao Nang in December: By the middle of this month weather turns dry but be prepared for some rain during the first half of the month.
Reading this, you will come to the conclusion that the best time of travel to Ao Nang should be from January till the middle of April.
If you want to enjoy empty beaches and low hotel prices however, you might want to consider the month of June until September for your holiday in Ao Nang.