The peak season typically runs from late April to June, coinciding with the April 30 and May 1 holidays. This year, however, butterflies began emerging in early April, around two to three weeks ahead of schedule, creating a striking natural spectacle.
Visitor numbers have surged. The park welcomed more than 12,300 visitors in March, including nearly 9,000 domestic tourists, with daily arrivals reaching tens of thousands during peak days in early April.
The early appearance of butterflies and fireflies reflects a combination of ecological factors, including temperature, humidity, rainfall and vegetation growth, and is considered an important biological indicator.
The phenomenon has turned the forest into a seasonal hotspot, with visitors travelling from across the country to photograph the colourful swarms. Many set out as early as 4 am, covering more than 100 kilometres from Hanoi to capture the butterflies at their most active.
“Thousands of butterflies fill the sky, I have never seen anything like it,” said Le Thu Hoa, a visitor from Hanoi, highlighting the cool air, ancient trees and vivid natural scenery.
Local photographers said demand has risen sharply since late March, with bookings fully scheduled as tourists seek to capture the rare seasonal display.
According to Do Hong Hai, acting deputy director of the centre for environmental education and services at Cuc Phuong National Park, authorities have strengthened guidance, urging visitors to respect the environment and avoid disturbing wildlife.
“We always remind visitors to come to the forest as attentive guests, not to rush, make noise or try to take what belongs to nature. Walk gently, speak softly and keep an open mind, and the forest will reveal its stories in its own way,” he said.