The National Weather Service has issued an excessive heat warning for south central Arizona that includes Maricopa County and the Phoenix area through 5 a.m. Sunday, Aug. 18.

High temperatures are forecast to reach between 112 to 115 degrees.

The forecast high for Fountain Hills is 108, with an increase in the humidity.

Overnight lows are expected to remain in the upper 80s to about 90.

People who need to be outdoors are urged to take extra precautions. When possible reschedule strenuous activity to early morning or evening. Schedule frequent breaks when working in the heat.

Know the signs and symptoms of heat exhaustion and heat stroke. Wear light weight and loose fitting clothing when possible and drink plenty of water.

Wearing a wide brimmed hat will help keep the body much cooler.

Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency. Call 911.