A Hmong community living 1,400 metres above sea level in Phu Hin Rong Kla National Park woke up on Tuesday morning to see the grass outside coated with frost in the northern province of Phitsanulok.
The temperature inside their homes was 3-4°C, but outdoors it was below zero and windy.
It was the second time this winter the highland village as woken to a frosty morning and temperatures below zero. The last freeze began on Dec 19 and lasted into Dec 21.
Known as Muban Thai Phukhao Phao Mong (Hmong hill-tribe village), this community is a popular destination for tourists, especially in the cold season when many young Thais are eager to camp out and indulge in the cool climate.
The morning frost in Phu Hin Rong Kla came in the face of a Meteorological Department forecast for warmer temperatures in upper Thailand, which usually results in sometimes eerie misty mornings at this time of year.
The warmer temperatures in upper Thailand mean less rain in the South, director-general Wanchai Sak-udomchai said on Tuesday.
Temperatures are expected to drop slightly around the end of this month and then rise in the following two to three weeks, he said. But a real cold spell is forecast again for the third week of February, he added.