The dangerously hot temperatures have already smashed previous high records in some cities. And as forecasts expect the mercury to rise even higher, widespread excessive heat advisories from the National Weather Service (NWS) have been put in place that affect more than 48 million people. “This type of heat is unusual for the month of June,” Julie Malingowski, a meteorologist with the NWS, told The Guardian, who added that most heatwaves in the western U.S. typically don’t occur until July or August. Forecasts from the agency don’t expect the heat to break until after Saturday in some areas, even after the sun goes down. “There’s no relief overnight, so if people don’t have proper air conditioning and can’t cool off, there’s not that respite,” Malingowski told The New York Times. RELATED: If You Live in These States, Don’t Drive With Your Windows Down, Officials Warn. The heatwave has led public health officials to recommend that anyone who lives in affected areas should stay indoors with air conditioning. According to Geoffrey Leung, MD, the public health officer for California’s Riverside County, the high temperatures expected this week “can be very unsafe, particularly for those who are very young, very old, and those with underlying health conditions.” He warned: “You do not want to ignore the potential for harm.” Officials from the NWS also warned that it’s never safe to leave a child, disabled person, or pet in your car, even for a short period of time. They suggest to remain hydrated by drinking plenty of fluids, wear light-colored and loose-fitting clothing, stay in the shade as much as possible when outdoors, and that any necessary strenuous outdoor activity should be scheduled for mornings. So, which areas are expected to see sweltering temperatures? These are the eight states that have currently issued widespread excessive heat advisories, according to the National Weather Service as of June 16. RELATED: Never Drink This During a Heat Wave, Experts Warn. RELATED: If You Live in These States, Brace Yourself for More Copperhead Snakes. RELATED: If You See This at the Beach, Don’t Go in the Water, Experts Warn. RELATED: If You Live Here, Prepare for More Sharks Than You’ve Ever Seen Before.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: If You Live Here, Prepare for a Mosquito Invasion Like You’ve Never Seen.