The Extreme Heat Warning is expected to affect residents and visitors in the Phoenix area and surrounding regions, including the Coachella Valley. Prolonged exposure to high temperatures can lead to heat-related illnesses such as heat exhaustion and heat stroke, which can be life-threatening. Vulnerable populations, including the elderly, children, and those with pre-existing health conditions, are at higher risk. Outdoor workers and individuals without access to air conditioning are also particularly vulnerable during this period.