PHOENIX — An excessive heat warning was issued for Thursday in Phoenix with temperatures expected to near 110 degrees.

The warning will go into effect at 10 a.m. and last until 8 p.m., according to the National Weather Service.

Thursday’s high is forecasted to hit 109 degrees.

Hot weather is expected to continue into the weekend, with the mercury expected to reach 106 degrees on Friday and Saturday before jumping up to 109 again on Sunday.

Under a recently adopted city of Phoenix policy, hiking trails on Camelback Mountain and at the Piestewa Peak trailhead are restricted from 11 a.m. to 5 p.m. while an excessive heat warning is active.

The Arizona Department of Health Services said almost 3,000 people a year wind up in emergency rooms around the state suffering from heat-related illnesses.

Homeless, infants, young children and adults 65 or older are among those who are most susceptible to heat-related illnesses.

To protect yourself against heat sickness, the health department recommends drinking water, dressing properly for hot weather, wearing sunscreen and avoiding strenuous activity, among other things.