Topography and climate

The Bangkok special administrative area covers 1,568.7 km2 (606 sq mi), making it the 68th largest province in Thailand. Much of the area is considered the city of Bangkok, therefore making it one of the largest cities in the world.[9] The Chao Phraya River, which stretches 372 km (231 mi), is Bangkok's main geographical feature. The Chao Phraya River basin, the area surrounding Bangkok, and the nearby provinces comprise a series of plains and river deltas that lead into the Bay of Bangkok about 30 km (19 mi) south of the city center. This gave rise to Bangkok's appellation as the "Venice of the East" due to the number of canals and passages that divide the area into separate patches of land. The city once used these canals, which were plentiful within Bangkok itself, as divisions for city districts. However, as the city grew in the second half of the 20th century, the plan was abandoned and a different system of division was adopted.

Bangkok lies about two meters (6.5 ft) above sea level, which causes problems for the protection of the city against floods during the monsoon season. Often after a downpour, water in canals and the river overflows the banks, resulting in massive floods. The Bangkok Metropolitan Administration (BMA) has recently installed higher banks alongside some canals to keep water levels from reaching street level. There are however some downsides for Bangkok's extensive canal routes, as the city is rumored to be sinking an average of two inches a year as it lies entirely on a swamp.

Bangkok has a tropical wet and dry climate under the Köppen climate classification system. Average temperatures in the city are about 2 °C (3.6 °F) higher than the ones shown for the Don Mueang Airport during the 1960-1990 period. The highest recorded maximum temperature is 40.8 °C (105.4 °F) in May 1983 and the lowest recorded minimum temperature is 9.9 °C (49.8 °F) in January 1955. The coldest temperatures were recorded in January 1924, January 1955, January 1974 and December 1999. The hottest year on record was 1997 (average yearly at Don Muang 30.0 °C) and the coldest was 1975 (average yearly at Don Muang 26.3 °C). The coldest daytime maximum temperature was 19.9 °C (68 °F), recorded in December 1992.