A long and intense heat wave is about to bake parts of Arizona, New Mexico and interior California. Meanwhile, a separate broiling front is causing life-threatening temperatures in South Florida.

The National Weather Service has warned people in several cities, including Phoenix and Miami, to avoid the sun this weekend.

Swaths of the Southwest and Florida are expected to see record-setting temperatures. But those regions are not the only ones to see unusual heat as of late.

Over the past week, the average global air temperature on several days appeared to be the hottest on record, going back to 1979, according to data from the National Oceanic and Atmospheric Administration.

Arizona

Over the next week, Phoenix is forecast to reach highs of 106 to 115 degrees. Forecasters said the worst of the heat will come in the middle of the week.

To put in perspective, the normal average high for July is 106.5 degrees, Isaac Smith, a meteorologist with the NWS office in Phoenix, told NPR.

The scorching temperatures come after eight consecutive days of highs above 110 degrees in Phoenix. The combination of hot, dry and windy conditions could also lead to fires, according to the NWS.

The excessive heat warning, which started on July 1, is expected to end on July 16. But Smith said there is a chance that the advisory, along with the extreme weather, will last beyond that.

Meanwhile, highs in Tucson will range between 108 to 115 degrees. A heat warning is in effect until Thursday. Over the weekend, the city is also expected to see some thunderstorms, caused by monsoon moisture building up along the state's border with Mexico.

Florida

On Saturday, all of South Florida — from Naples to Miami to Fort Lauderdale — was under a heat advisory.

The region's heat index, which indicates what the temperature feels like, ranged from 105 to 109 degrees on Saturday afternoon, the NWS said. Health experts deem a heat index above 103 degrees as dangerous.

Sweltering conditions will likely continue until Friday.

In Miami, this year has proven to be the hottest on record. The city has already broken 15 record daily temperatures — seven of which took place in June, according to member station WLRN.

That is especially dangerous for the region's outdoor workers, who number more than 100,000 people, WLRN reported.

How to stay safe amid extreme heat

Heat waves can be a serious danger to your health. Each year in the U.S., an average of 702 heat-related deaths occur and an average of 9,235 people are hospitalized due to heat, according to the Centers for Disease Control and Prevention.

The safest bet is to stay indoors in air-conditioning as much as possible while the heat wave rides out. If your home does not have air conditioning, go to the shopping mall or public library. You can also check your local health department to see if there are any cooling shelters near you.

If you have to go outside, the CDC says make sure you are wearing light-weight, light-colored, loose fitting clothes, as well as drink lots of water — and sugary drinks do not count.

Also, check in on your older relatives and neighbors as older adults tend to be most at risk for heat exposure. Children, people with disabilities and those who work outside also tend to be at greater risk.