Thailand will enter the rainy season on Friday, the weather agency said on Wednesday, but a drought is expected next month.
The Meteorological Department announced the start of the wet season on Friday and it will go through mid-October except in the southern region, where it will last three more months.
Department director-general Chomparee Chumpurat warned that a shortage of rainfall would be possible for one month from mid-June and it could spell drought in farmland outside the irrigation system.
The country would encounter heavy rain in August and September, especially in the upper part of the country, she added.
The department on Wednesday also warned that Tropical Cyclone Asani could cause downpours and flash floods in some areas over the next 24 hours before the storm makes landfall in central India.
The storm has triggered flooding in the southern region, with Surat Thani, Nakhon Si Thammarat and Songkhla among the provinces hit the hardest.