Cambodia is located in Southeastern Asia, bordering the Gulf of Thailand, between Thailand, Vietnam, and Laos. Cambodia falls within several well-defined geographic regions. The largest part of the country--about 75 percent of the total-- consists of the Tonle Sap Basin and the Mekong Lowlands. To the southeast of this great basin is the Mekong Delta, which extends through Vietnam to the South China Sea. The basin and delta regions are rimmed with mountain ranges to the southwest (the Cardamom Mountains the Elephant Range) and to the north (Dangrek Mountains). Higher land to the northeast and to the east merges into the Central Highlands of southern Vietnam.
Climate: Cambodia is is dominated by the monsoons, which are known as tropical wet and dry because of the distinctly marked seasonal differences. The monsoonal airflows are caused by annual alternating high pressure and low pressure over the Central Asian landmass. In summer, moisture-laden air--the southwest monsoon--is drawn landward from the Indian Ocean. The flow is reversed during the winter, and the northeast monsoon sends back dry air. The southwest monsoon brings the rainy season from mid-May to mid-September or to early October, and the northeast monsoon flow of drier and cooler air lasts from early November to March. The southern third of the country has a two-month dry season; the northern two-thirds, a four-month one. Short transitional periods, which are marked by some difference in humidity but by little change in temperature, intervene between the alternating seasons. Temperatures are fairly uniform throughout the Tonle Sap Basin area, with only small variations from the average annual mean of around 25°C. The maximum mean is about 28°C; the minimum mean, about 22°C. Maximum temperatures of higher than 32°C, however, are common and, just before the start of the rainy season, they may rise to more than 38°C. Minimum temperatures rarely fall below 10°C. January is the coldest month, and April is the warmest. Typhoons--tropical cyclones--that often devastate coastal Vietnam rarely cause damage inCambodia