The national park, which spans 484 square kilometres across the districts of Samoeng, San Pa Tong, Hang Dong and Mae Wang, announced that it was closing until the situation returns to normal.
The Thai Meteorological Department has announced that most of Thailand will be hit by heavy rain on Monday and warned people to beware of flash floods and overflows, especially along the foothills near waterways and lowlands.
One of the famous attractions in Ob Khan National Park is Khun Tian, the highest peak at 1,550 metres above sea level that features panoramic views of the park, the adjacent Doi Suthep-Pui National Park to the east, and Mae Wang National Park and Doi Inthanon National Park to the west.
