Modern climatological data for Thailand began with the important contributions of meteorologists in the Royal Irrigation Department in Bangkok, and in particular those of H. Brandli, a Swiss, who commenced his work about 1900 and eventually was collecting rainfall data from 88 rainfall stations in all parts of the Kingdom. For Bangkok published observations of the most important meteorological elements go back considerably further.
During the late 1920's first-class weather stations were established at Rangsit, north of Bangkok, at Chiangmai, Northern Thailand, and at Pattani on the Peninsula East Coast. The aerial activity in Southeast Asia during and following World War II--first military, then commercial--has stimulated meteorological work in this region. Major meteorological stations are now found in 37 towns and cities.