Based on quality-controlled daily station data, long-termtrends and variability of total and extreme precipitation
indices during 1955–2014 were examined for Thailand. An analysis showed that while precipitation events have
been less frequent across most of Thailand, they have become more intense. Moreover, the indices measuring the
magnitude of intense precipitation events indicate a trend toward wetter conditions, with heavy precipitation
contributing a greater fraction to annual totals. One consequence of this change is the increased frequency and
severity of flash floods as recently evidenced in many parts of Thailand. On interannual-to-interdecadal time
scales, significant relationships between variability of precipitation indices and the indices for the state of El
Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) were found. These results provide additional
evidence that large-scale climate phenomena in the Pacific Ocean are remote drivers of variability in
Thailand's total and extreme precipitation. Thailand tended to have greater amounts of precipitation and more
extreme events during La Niña years and the PDO cool phase, and vice versa during El Niño years and the PDO
warm phase. Another noteworthy finding is that in 2011 Thailand experienced extensive flooding in a year characterized
by exceptionally extreme precipitation events. Our results are consistent with the regional studies for
the Asia-Pacific Network. However, this study provides a more detailed picture of coherent trends at a station
scale and documents changes that have occurred in the twenty-first century, both of which help to inform decisions
concerning effective management strategies.