Heat dome scorches cities coast to coast as dangerous temperatures enter 2nd week

Sixty-five million Americans from coast to coast are under heat alerts.

Sixty-five million Americans from coast to coast are under heat alerts as the life-threatening heat dome continues for the second week.

The Northeast, Southeast and West all saw daily record temperatures shattered this weekend, including 98 degrees in Philadelphia; 100 degrees in Greenville, Mississippi; and 108 degrees in Merced, California.

This weekend, Washington, D.C., and Baltimore hit 100 degrees for the first time in June in 12 years.

On Monday, the dangerous heat is impacting the Southeast, the Deep South and the West.

Areas in South Dakota, Iowa and Minnesota that faced catastrophic flooding in recent days will also be dealing with the scorching heat on Monday.

This week, temperatures will remain extremely hot in the South, from Texas to Kansas to Arkansas to Florida.

The greatest heat risk will be in Oklahoma. Oklahoma City is under extreme heat risk -- the highest level -- due to the combination of hot afternoons and very warm nights.

There are hundreds of deaths each year in the U.S. due to excessive heat, according to CDC WONDER, an online database, and scientists caution that the actual number of heat-related deaths is likely higher.

Click here for tips on how to stay safe in the heat.