(CNN)The summer solstice officially occurs on June 20, and it'll arrive with a vengeance for the desert Southwest as temperatures soar near the 110°F-120°F range.
Extreme heat will bake Southwest U.S.
Record-breaking heat will be possible for parts of Southern California and Arizona as an unusually strong ridge of high pressure strengthens across the region.
The National Weather Service has already issued excessive heat watches and warnings for more than 20 million people, including residents of Phoenix, Los Angeles and Las Vegas. These heat warnings mean that a prolonged period of extreme and dangerous temperatures will occur in the warned area.
They also serve as a reminder that pets and young children should never be left unattended in vehicles under any circumstances.
Phoenix is projected to have a high temperature of 119°F next Monday. It has been 1084 days since the last time the city hit 119°F, back in 2013.
Phoenix has only observed three 120°F days since record keeping began in 1895. The hottest day ever recorded in Phoenix was 122°F, set back on June 26, 1990. We could get close to breaking the all-time record high on Sunday or Monday.
The Phoenix National Weather Service is calling this a "rare, dangerous, and deadly heat wave." All residents are urged to stay hydrated and to limit their time outdoors.
Cooling centers will be available to residents who find themselves without access to air conditioning, as well as hydration stations. To find a cooling center or hydration station near you, visit http://coolme.today.