Study weather information, as an ill-timed trip can mean pouring rain, debilitating humidity, or seas too rough for diving or beach activity. The high season for tourism throughout the kingdom is the North American/European winter period, mid-October through late February. Prices skyrocket and hotels fill up then, so be sure to make advance reservations. Off-season weather, however, is not intolerable, and some travelers report joyfully trading the crowded beaches and high prices of high-season for a bit of off-peak discomfort. Low-season is generally comprised of the odd rainy afternoon, significant savings, and a lot more elbow room.

Thailand has two distinct climate zones: tropical in the south and tropical savanna in the north. The northern and central areas of the country (including Bangkok) experience three distinct seasons. The hot season lasts from March to May, with temperatures averaging in the upper nineties Fahrenheit (mid-30s Celsius), and with April being the hottest month. Normally, this period sees sporadic rain.

In recent years, however, the rainy season has begun in April and has lasted, on and off, until late November, or even December. The average temperature is 84ŶF (29ŶC) with 90% humidity. While the rainy season brings heavy downpours, it is rare to see an all-day episode. From June, daily showers will usually come in the late afternoon or evening for 3 to 4 hours; often bringing floods and forcing traffic to a standstill. Trekking in the north is not recommended during this time. In Bangkok, expect smog from April to August.

The cool season, from November to February, has temperatures from the high 70ŶF to low 80ŶF (26ŶC-30ŶC), with infrequent showers. In the north, the cool season coincides with the peak season for tourism. Daily temperatures can drop as low as 60ŶF (16ŶC) in Chiang Mai and 41ŶF (5ŶC) in the hills; 1 or 2 nights may even see frost.

The Southern Thai Peninsula has intermittent showers year-round and daily downpours during the rainy season (temperatures average in the low 80s Fahrenheit/30s Celsius). If you're traveling to Phuket or Koh Samui, it would be helpful to note that the two islands alternate peak seasons. Optimal weather on Phuket occurs between November and April, when the island welcomes the highest numbers of travelers. Conversely, Koh Samui's great weather lasts from about February to October.

Holidays

Many holidays are based on the Thai lunar calendar, falling on the full moon of each month; check with the Tourism Authority of Thailand (TAT; www.tat.or.th) for the current year's schedule.

On National and Buddhist holidays, as well as polling days, government offices, banks, small shops, and offices -- as well as some restaurants and bars -- usually close. By law, bars cannot serve alcohol on HM Queen Sirikit's birthday in August, nor on HM King Bhumibol's birthday in December. Note: In most cases there will be little advance warning given to shop, restaurant, or bar customers. Public transport still runs on holidays, though.

January to March

Thailand celebrates New Year's Day the same as the rest of the world. In late February or early March (depending on the lunar cycle) is Makha Bucha Day, when temples celebrate Buddha preaching to his disciples.

April

Chakri Memorial Day (April 6) commemorates the founding of the current Chakri dynasty.

Songkran is the New Year according to the Thai calendar, and it's an event that begins on April 13 and lasts from 3 to 10 days. After honoring local monks and family elders, folks hit the streets for massive water fights. Be warned -- foreigners are the Thais' favorite target and areas like Khao San Road become messy war zones where everyone gets soaked (police included) and then covered in flour or colored powder. Truck-mounted power hoses can cause damage, and cellphones, cameras, and valuables should be kept in Ziploc bags. Wear your oldest clothes -- anyone expecting to stay dry will be sorely disappointed!

May

National Labor Day falls on the 1st, Coronation Day (celebrating the coronation of HM King Bhumibol in 1946) is on the 5th, while the 14th is Royal Ploughing Day, the first day of the rice-planting cycle, which is celebrated with a traditional Brahman parade. Visakha Bucha Day, marking the birth, enlightenment, and death of the Buddha, falls around mid-May, depending on the lunar calendar.

July

Thais celebrate the Buddhist Lent immediately following Asarnha Bucha Day in mid-July (depending on the lunar calendar) signaling the beginning of the rains' retreat and the 3-month period of meditation for all Buddhist monks -- this was the day that the Buddha delivered his first sermon to his first five disciples.

August

August 12 honors the birthday of HM Queen Sirikit and is also Mother's Day.

October

On October 23, Chulalongkorn Day, the country's favorite king, Rama V, is remembered.

November

Loy Krathong, in early November, is Thailand's most romantic festival, although it's not usually a public holiday. At dusk, handmade banana leaf vessels are launched down rivers and lanterns are hoisted into the sky in order to symbolize the release of sins. The most spectacular celebrations are in Ayutthaya, Sukhothai, and Chiang Mai.

December

December 5 marks HM King Bhumibol's birthday and is also Father's Day. December 10 is Constitution Day and recognizes Thailand's first constitution in 1932.

Check with the Tourist Authority of Thailand (tel. 1672; www.tat.org) for more information on the events listed below as well as for other holidays celebrated throughout the country.