Firefighters responded to Piestewa Peak Monday afternoon after a hiker reported issues related to the heat.
Officials said the hiker, who was identified as a 33-year-old male, was suffering symptoms of heat-related illness.
The temperature in Phoenix was 104 degrees Fahrenheit as of 2:30 p.m.
Fire crews helped the man down the trail. He called 911 after he wasn't sure whether he could make it all the way down after reaching the top of the trail.
He had been out for about an hour and a half and had plenty of water, according to the Phoenix Fire Department.
The hiker was evaluated and refused further treatment.
The call was the second of the day for Phoenix fire crews, who earlier airlifted three people--including a 12-year-old boy--from Echo Canyon on Camelback Mountain.
No other information was immediately available.
Air15 is launching to the scene. Stay with ABC15, abc15.com and ABC15 Mobile for updates.