Hundreds of butterflies swarmed a reservoir after rain in Thailand.

Footage shows clouds of butterflies fluttering near the Lam Chae Reservoir at the Thap Lan National Park in Nakhon Ratchasima province following a downpour on May 18.

Khampa Songkratok, 50, chairman of the Lam Chae Dam tourist boat service group, said the butterflies emerged after the rain helped cool the scorching temperatures.

He added that the rainwater trickled down to the streams and waterfalls at the national park, making the tourist spot more attractive.

He said: 'This area has hundreds of different types of butterflies in many different colors. They fly together in flocks all over the area. If tourists have the opportunity to travel here during this period, I can guarantee that it is definitely worth it and you won't be disappointed.'

The water level at the reservoir, which receded during the recent heat wave in Thailand, has increased to 101.88 million cubic metres or 36.76 per cent of its total capacity.