heat wave

The recent heat has been record-setting in parts of Florida, and in some unusual ways.

Sunday's high temperature of 98 degrees in Jacksonville tied its daily record for August 11 set in 2011. This is a type of record one would normally expect during a heat wave.

However, high levels of humidity have prevented the mercury from falling as much as it normally does overnight. The morning lows have been so warm, they’ve also broken a few records across the state.

A major heat wave this weekend is expected to affect two-thirds of the country, hitting parts of the Northeast and the Midwest the hardest. Temperatures could exceed 100 degrees in several cities, with heat indexes of up to 115 degrees. Cities have already begun preparing for the extreme weather by opening cooling centers, extending pool hours and canceling outdoor activities and community events.