Some of Phoenix’s most popular hiking trails will be closed this summer on days when the National Weather Service issues an excessive heat warning.

Phoenix officials said Camelback Mountain's Echo and Cholla trails and all trails associated with Piestewa Peak Trailhead in the Phoenix Mountains Preserve will close from 11 a.m. to 5 p.m. when a warning is issued.

“During excessive heat warnings, trail access is limited, parking lot gates will be closed and sign(s) will be posted,” a city release stated.

Closure information will be posted on the Phoenix Parks and Recreation Department's website and social media accounts and to local resorts and hotels.

Phoenix park rangers will be on duty to remind visitors of the restrictions.

Extended summer hours are in effect annually from June through September at North Mountain Park and Piestewa Peak Trailhead in the Phoenix Mountains Preserve and Pima Canyon Trailhead in South Mountain Park/Preserve, city officials said.

To provide an extra two hours of availability and promote hiking after 7 p.m., parking lot entrances are open until 9 p.m. at those locations. Year-round at those three trailheads, parking lots open at 5 a.m., and trails are open until 11 p.m., according to the release.

All other trails within the Phoenix parks system will remain open, officials said.