YELLOWSTONE NATIONAL PARK, Wyoming (AP) — A record number of people visited Yellowstone National Park in May.

The National Park Service said Friday the park got almost 447,000 visits in May, up 6 percent compared with May last year.

Year-to-date visitation is down slightly from the almost 600,000 people who had been to Yellowstone by this point in 2016. Even so, almost 571,000 people have been to Yellowstone in 2018, making for a busy year so far.

Yellowstone, Grand Canyon and Yosemite are among the busiest national parks in the western U.S. Each park gets roughly 4 million to 6 million visits a year.

Yellowstone’s peak season is May through September. Relatively few people visit during winter, when most of Yellowstone is accessible only by snowcoach and snowmobile.