The temperature in Thailand this summer will be 1-2 degrees Celsius warmer than last year, Meteorological Department director-general Phuwiang Prakam-min said on Saturday.
And it will hit 42-43C in seven provinces in upper Thailand, he added.
Marking summer on the calendar as February 21 to mid-May, Phuwiang said daytime temperatures in March and April would reach 40C in much of the North, Northeast, Central and Eastern regions.
He does not foresee the record set on April 28, 2016, when Mae Hong Son sweltered at 44.6C, being broken.
But Mae Hong Son is one of the seven provinces forecast to reach 42-43C this year, the others being Lampang, Uttaradit, Sukhothai, Tak, Nakhon Sawan and Kanchanaburi.
In the South, the maximum temperature will be 38-39C in Prachuap Khiri Khan, Surat Thani, Nakhon Si Thammarat, Yala, Krabi, Trang and Satun, accompanied by occasional rain and waves at sea up to a metre high, Phuwiang said.
Rain will increase towards the end of April and waves will be up to three metres high, he predicted.
The weather in Pattaya in Chon Buri will match that of the South, with a maximum temperature of 35-37C in April.