Bangkok 

Bangkok (Thai: กรุงเทพฯ Krung Thep) is the capital of Thailand and, with a population of over eleven million inhabitants, by far its largest city. Its high-rise buildings, heavy traffic congestion, intense heat and naughty nightlife do not immediately give you a warm welcome — but don't let your first impression mislead you. It is one of Asia's most cosmopolitan cities with magnificent temples and palaces, authentic canals, busy markets and a vibrant nightlife that has something for everyone.

For years, it was only a small trading post at the banks of the Chao Phraya river, until King Rama I, the first monarch of the present Chakri dynasty, turned it into the capital of Siam in 1782, after the burning of Ayutthaya by Burmese invaders. Since then, Bangkok has turned into a national treasure house and functions as Thailand's spiritual, cultural, political, commercial, educational and diplomatic center. 

Just under 14 degrees north of the Equator, Bangkok is a tropical metropolis that is also one of the most traveller-friendly cities in Asia. A furious assault on the senses, visitors are immediately confronted by the heat, the pollution and the irrepressible smile that accompanies many Thais. Despite the sensationalized international news reports and first impressions, the city is surprisingly safe (except from some petty crimes) and more organized than it initially appears, and full of hidden gems waiting to be discovered. The high relative humidity and warm temperature favour the growth of tropical plants — you'll find exotic orchids and delicious fruit everywhere. Bougainvillea and frangipani bloom practically all over the city. Thai cuisine is justifiably famous, varied, and affordable. Bangkok for many represents the quintessential Asian capital. Saffron-robed monks, garish neon signs, graceful Thai architecture, spicy dishes, colourful markets, traffic jams, and the tropical climate come together in a happy coincidence. It is difficult to leave with lukewarm impressions of the city. 

Climate

According to the World Meteorological Organization, Bangkok is the world's hottest city. Located just 14 degrees north of the Equator, Bangkok is sunny at any time of the year with temperatures over 30°C (86°F).

The most pleasant time to visit is the cool season that lasts from November till February. It is both the coolest and driest period — the Emerald Buddha statue in Wat Phra Kaew even wears a scarf during this period! Don't think that's necessary though — daytime temperatures still hover around 30°C (86°F), but it does cool down into the lower 20s as it gets dark (lower 70s in Fahrenheit). March and April represent the hot season, and hot it is — 35°C (95°F) on average, but don't be surprised to see temperatures rising into the 40s °C (around 100 °F+). This is the worst season to visit Bangkok, so plan in a lot of air-conditioned shopping mall visits and get a hotel with a swimming pool. Then there's the wet season that runs from May till October. Expect massive downpours resulting in floods all over the city, and spells of thunder at times. It's not all bad though — the afternoon showers are actually a pleasant way to cool down from the heat, and while they may last all day, usually they're over within an hour. Extreme rainfall happens in September and October, so these months are best avoided.

Whatever season you're visiting, don't take the weather lightly — temple-tramping in the middle of the soaring afternoon sun can be a challenge, so come well-prepared. Dress lightly for the weather, but keep in mind that some palaces and temples (notably the Grand Palace) have a strict dress code. Also be sure, and this cannot be said enough, drink enough fluids! You don't have a reason not to, as 7-Elevens and other convenience stores are abundant in Bangkok and they sell cooled beverages for as little as 10 baht. Locals get their water from "reverse osmosis" purified water machines that fill up a bottle for less than 3 baht. 

While not particularly high class, street food is among the most delicious food and can be found all over Bangkok — wherever you're staying, you rarely have to walk more than 100 meters for a cart of street restaurant. Many of street vendors sell satay (สะเต๊ะ) with hot sauce for 5 to 10 baht a piece.

One of Thailand's national dishes you can try is pad thai (ผัดไทย), stir-fried rice noodles with eggs, fish sauce, tamarind juice and red chilli pepper. It can be prepared for you on one of the ubiquitous carts, or in a street restaurant for about 50 baht. You can order it with chicken (kai) or shrimps (kung). Another one of Thailand's national dishes you should try is tom yam kung (ต้มยำกุ้ง), a sour soup with prawns, lemongrass and galangal — beware, as it is very spicy! Khao man kai (ข้าวมันไก่) is another popular street food. You can identify it at stalls displaying boiled chicken. Served with a bowl of fragrant chicken soup is a mound of rice topped with sliced chicken pieces and cucumber. Side sauces are spicy and go well with the bland chicken and rice. You can sometimes add optional liver and gizzard if that is your taste. If you like sweets, try to find a kanom roti (โรตี) street vendor. The crepe-like dessert is filled with sweetened condensed milk, lots of sugar, and can also have bananas inside. Also fun to watch them being made. 

source: http://wikitravel.org/en/Bangkok