Generally there are three seasons in Phuket, Krabi, Phang Nga and environs.  March, April and May are considered a distinct period because of the heat and humidity.  The two accompanying seasons govern activities in the Andaman Sea: the northeast monsoon, which runs from November to May brings consistently sunny weather and calm seas; the southwest monsoon, running from May to October brings the most unpredictable and rainy weather.  Temperatures vary between 21 and 34 degrees Centigrade and water temperatures from 26 to 28 degrees through the year.

January

The weather is generally dry and sunny, seas fairly calm and the sky bright blue.  Very good weather for sea canoeing and other watersport activities.  Getting hotter towards the end of the month, but still northwest monsoon conditions.
For shoppers, this month often brings post Christmas and New Year sales- and good bargains are to be found.  Although quieter than December, January can be a very busy month due to summer holidays in the Southern Hemisphere.  Good time to visit Phang Nga.

February

Windsurfing, yachting and dinghy sailing are all recommended during this month.  Seas are generally flat and winds between 25 and 30 knots.  Skies should be clear and visibility good.  Either late February or early March brings in the Chinese New Year (trut jinn in Thai).  The exact date depends upon the moon.  Due to Phuket’s Chinese influences and the large numbers of Chinese descendants living on the island, the festival is celebrated with fireworks, lion dances, the traditional house cleaning and paying off of debts.  Festivities occur all across the island, but are particularly centred in Phuket Town.

March

The weather generally becomes warmer and more humid, but stil 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. The seas may become to little more lively –perfect for windsurfing, yachting  and other sail-driven activity.

For sailors, west coast anchorages are secure.  A good time of year for sightseeing perhaps a few trips into island’s interior to view the many wats, see Ton Sai waterfall or take a trek into the jungle on elephent-back.

April

The weather conditions generally remain exactly the same as March.
April sees the most frenetic of all Thai festivals: Songkran(13th – 15th).  This is the Lunar New Year’s celebration in Thailand and traditionally revolved around Buddha images being bathed in water and younger Thais showing respect to monks and elders by sprinkling water over their hands.  This has evolved into a mass soaking of anyone within spraying distance of an ice-cold bucket of water or within spraying distance of a hosepipe.  Be prepared to get wet- no matter how you are dressed.

May

June

June is the beginning of the rainy season, although the weather can be as in March.  Heavy seas and surf often make some watersports uncomfortable for all but the accomplished sailor, windsurfer or surfer.  Often, however, there is a break in the weather which locals call a “mini peak season”.  A good time for gamefishing.
Some years, as in 1999, the weather in June has been as perfect as high season, with calm seas, light winds and clear blue sky.  No matter what the weather, the northern bays remain calm.

July

Likely to be a little rougher than June, although Phang Nga Bay is still very suitable for generally messing about in boats, or in the water.  Some days may be misty, but this adds to the real beauty of its limestone peaks.
Mid-July sees the celebration of Asanha Puja: a full-moon festival celebrating the first sermon preached by Buddha.  Buddhist “Lent” begins in mid to late July and is the period when young men enter monkhood for the rainy season and ordained monks remain in a single monastery for three months.

August

A good gamefishing off the sides of outlying islands such as Koh Racha Yai.  Heavy seas underdowns and rip tides can make swimming difficult on some beaches- red flags on the beach mean don’t swim under any circumstances.  Phang Nga Bay is still fine for most watersports and the east coast of the island is most sheltered-particularly Chalong.
August 12th is Her Majesty The Queen’s birthday and is a public holiday.  Thailand also celebrates the Queen’s birthday as national Mothers’ Day.

September

This is potentially the wettest month, along with October, often with gusty winds.
Like the rest of the rainy season, however, there are often still “mini peak seasons” with extended spells of clear and dry weather.
A good month for fighting fish, 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, as may restaurants have high and low season menus.

October

The beginning of the month can be the wettest and windiest but the weather generally improves as November approaches, winds change  direction and the northeast monsoon takes over from the southwest.
October is usually the month when the Vegetaria Festival is celebrated in Phuket and Trang.  Chinese Buddhists eat only vegetarian food and there are various ceremonies and processions- Phuket Town is the best place to observe these processions, some of which involve self-mortification.

November

The from the northwest monsoon means that this time of year is the most perfect on Phuket.  This is the beginning of the peak season, lasting until May.  Ideal for all things nautical.  The Phuket International Sport Fishing Competition is held this month.
Culturally the month sees 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.  This embarrass the floating away of cares and good wishes for the future – beautiful and moving sight.

December

The game fishing season has really begun and this is a good time to catch marlin, tuna and sailfish.  The weather should still be dry and sunny, with calm seas and a light evening surf:ideal for water-skiing and parasailing.  The annual King’s Cup Regatta, a spectacular international event, is held from December 5th  – 11th.
December 5th is His Majesty The King’s birthday, a public holiday and is treated with reverence and some celebration: many lights adorn temples and shrines across the island.  Christmas and New Year are celebrated throughout Phuket.  A very busy time of year.