This study aims to investigate changes in rainfall in terms of trends, variability, spatial and
temporal distributions, and extremes in the Huai Luang watershed. The trend analysis was
applied to the time series of rainfall data for 32 years from 1982-2013. Changes in spatial and
temporal rainfall distributions and extremes were investigated by comparing the 2 periods of the
rainfall data between 1982-1997 and 1998-2013. Frequency analysis of annual maximum daily
rainfall was applied to determine changes in extreme rainfall for different return periods at three
stations located upstream, middle and downstream of the watershed. The results of this work
show significantly increasing trends in annual rainfall, spatial variations and extreme daily
rainfall in the Huai Luang watershed. The extreme rainfall resulted in increasing floods in last
decade. Spatial and temporal rainfall distributions are also changing. The lower part of the
watershed will have more rain. Further studies on potential impacts of rainfall changes on flood
risk, water resources management, urbanization and agriculture development in the Huai Luang
watershed are recommended to support preparation of adaptation strategies for mitigating
potential negative impacts.