Unusually hot summer days have become more common across the U.S. and overnight lows aren't as low as they used to be. In fact, all of Georgia's cities saw higher minimum temperatures this past July when compared to the 20th century average.

Since the 1960s, Atlanta has added an additional 22 days of the year where the temperature reached as high as 90 degrees. Two researchers from Spelman College are leading a citywide study into which Atlanta neighborhoods get the hottest, which stay cooler and who lives where.

Intense heat is getting worse with climate change as small increases in temperature can magnify extremes, according to a study by Climate Central, an...