The Extreme Heat Warning affects residents across the Phoenix metro area and southwestern Arizona, including vulnerable populations such as the elderly, children, and those with pre-existing health conditions. The combination of high daytime temperatures and warm overnight lows increases the risk of heat-related illnesses, such as heat exhaustion and heatstroke. Pets and children are particularly at risk if left in vehicles, even for short periods. Outdoor workers and individuals engaging in strenuous activities should exercise caution and take frequent breaks to avoid heat-related complications.