In order to mitigate heat-related incidents and promote visitor safety, Tonto National Monument will enter into annual summer hours to hike to the Lower Cliff Dwelling. Starting June 1, 2023 and ending August 31, 2023 hiking hours will be 8:00 a.m. to 12:00 p.m. (noon). Visitors who wish to hike to the Lower Cliff Dwelling need to begin their hike before 12:00 p.m.

No fees will be charged after 12:00 p.m. and Interagency Passes will not be available. The Visitor Center will remain open daily from 8:00 a.m. to 5:00 p.m. featuring an engaging 20-minute film about the monument and an opportunity to find items to remember your visit in the Western National Parks Association Park Store. 

Original source can be found here