Origin of Lychees. An attractive and rare sub tropical fruit tree that bears a luscious red fruit, the Lychee originated over 2000 years ago first in the north tropical rainforests and mountain forests of Southern China, where it is a dominant tree species. (this is according to www.lycheesonline.com/origin.cfm)

Now it is present in several countries with the right climate such as North Vietnam, Cambodia,Mauritius (in upper part of Mauritius where there is sufficient rain, but not upper most part )

According to wikipedia:- Lychees are extensively grown in China, India, Thailand, Vietnam and the rest of tropical Southeast Asia, the Indian Subcontinent, and more recently in South Africa, Brazil, the Caribbean, Australia and the United States. They require a tropical climate that is frost-free and is not below the temperature of −4 °C (25 °F). Lychees also require a climate with high summer heat, rainfall, and humidity. Growth is best on well-drained, slightly acidic soils rich in organic matter and mulch.