January
The weather is generally dry and sunny, the sea is fairly calm and the sky is bright blue which results in very good weather for sea canoeing, diving and snorkeling. It gets hotter towards the end of the month, but the northwest monsoon conditions still prevail. Although quieter than December, January can be a very busy month due to summer holidays in the Southern Hemisphere, Christmas and New Year. It's a good time to visit Khao Lak.
February
The sea is generally flat and the wind is not strong, with not much rain. Either late February or early March brings in the Chinese New Year (trut jeen in Thai) and the exact date depends upon the moon. There are many diving boats and divers at Similan, with the under water visibility being good at this time.
March
The weather generally becomes warmer and more humid, but you can still expect plenty of sunshine. For scuba divers, visibility may slightly diminish, but increased plankton counts improve your chance of seeing whale sharks and manta rays.
April
The weather conditions generally remain exactly the same as March. April is the month of Thai festivals, with Songkran from the 13th to the 15th. This is the Lunar New Year celebration in Thailand and traditionally revolves around Buddha images being bathed in water and younger Thais showing respect to monks and elders by sprinkling water over their hands. Be prepared to get wet - no matter how you are dressed. The diving is good in April with a good chance of seeing whale sharks and manta rays. The sea is flat and it's the warmest month of the year.
May
Generally the weather is fine and the sea is calm, but in the middle of May the weather becomes little less predictable. The Similan national park is closed at the end of this month. May
June
June is the beginning of the rainy season, although the weather can be much the same as in March. The mountains start to get greener, the waterfalls start to have a lot of water and it's a good time to go treking in Khao Lak national park.
July
Much like June, some days are rainy and some days are sunny. The sea can be rough and the beaches tend to be empty. There are not many tourists here, which makes it good for people who want some peace and quiet. The temperature is about 30 degrees Centigrade, with less chance of getting sunburn.
August
Heavy sea under currents and rip tides can make swimming difficult on some beaches, red flags on the beach mean don't swim under any circumstances as the waves can be big. This is a good to visit the waterfalls around Khao Lak as there will be a lot of water and they look very beautiful. The beaches are empty and you can have the whole beach to yourself.
September
This is potentially the wettest month, along with October and there are often gusty winds. Like the rest of the rainy season, however, there are often still peak seasons with extended spells of clear and dry weather. September and October usually have the lowest hotel occupancy rates, so good bargains are to be found if you are prepared to gamble on the weather, the general cost of living can be lower.
October
The beginning of the month can be the wettest and windiest but the weather generally improves as November approaches, the winds change direction and the northeast monsoon takes over from the southwest. October is usually the month when the Vegetarian Festival is celebrated in Khao Lak and you will see the yellow flags at the side road when you drive through Khao Lak. Chinese Buddhists eat only vegetarian food and there are various ceremonies and processions. Khao Lak Scuba Adventures first diving trips start on the 15th of this month.
November
The northwest monsoon means that this time of year is the most perfect. This is the beginning of the peak season, lasting until May and is ideal for all things nautical. Culturally the month see the annual Loi Krathong, or Full Moon Festival, when small baskets or boats made from banana leaves are set afloat filled with flowers, incense, candles and a coin.
December
The weather should still be dry and sunny, with calm seas, making this a good month for diving. Christmas and New Year make this a very busy time of year for Khao lak.
