"It's solely because of the global economic recession. This hit Thailand's three main export categories - auto, electronic and home appliances," said Permanent Secretary Siripol Yodmuangcharoen at the press conference on Thursday.
In terms of value, it is the lowest in two years, he said.
Imports in the month also dropped 37.6 per cent, leading to the trade surplus of $1.38 billion.
Thailand's exports have plunged for three consecutive months.
Meanwhile, Bangkok Bank Research estimated that Thailand's exports may expand less than 1 per cent or contract as much as 10 per cent this year.
In the research, while imports are expected to shrink 3-14 per cent this year, Thailand's trade surplus and current account surplus would be 1-2 per cent of gross domestic product.
The bank said GDP may contract 1 per cent or grow 1.5 per cent, due mainly to recession in key importing countries. This pessimistic scenario is painted though domestic political instability is less severe and the government plans to spend an extra budget to boost the economy.