Extreme heat will smother the South from Arizona to Florida

Phoenix is on track to surpass the city's heat wave record of 18 consecutive days of 110 degrees and above.

Caitlin O'Hara / Caitlin O'Hara

After a weekend of broiling heat waves in the Southwest and South Florida, more extreme heat is forecast to build throughout the week.

Forecasters say residents of both regions should stay out of the sun as much as possible.

Across the country, heat waves are getting hotter, lasting longer and becoming more unpredictable. Jeff Goodell, the author of The Heat Will Kill You First, called it a dire consequence of climate change.