Happy Nude Hiking Day. Picture: Instagram

While not an officially recognised holiday by any country or municipality, Nude Hiking Day — or Hike Naked Day, as it’s also known — is reportedly observed by hikers across the world as a way to celebrate the northern summer solstice, Fox News reports.

But the US state of Colorado, in particular, is so wary of underdressed outdoorsmen that the state’s Parks and Wilderness organisation felt the need to deter local residents by threatening to ticket hikers for indecent exposure, reports Denver7 News.

“We would ask them to leave or put on clothing,” added Lauren Truitt of Colorado Parks and Wildlife (CPAW), which oversees 42 state parks and 300 state wildlife areas.

The US Bureau of Land Management (BLM), on the other hand, claims it will deal with nude hikers on a case-by-case basis, and punishment would depend on how much of a nuisance each nudist is being, according to Denver7.

Still, “anyone participating should remember that state and county law apply on public lands, as well,” warned a BLM public affairs specialist.

Despite warnings from the CPAW and BLM, Instagram evidence shows that the nation’s most confident backpackers are still suiting up (figuratively) and hitting the trails in Colorado and elsewhere:

Denver7 further points out that a quick Google search for nude hiking groups results in “dozen” of results in the Colorado area.

Bring bug spray.

This article originally appeared on Fox News and was reproduced with permission.