. On July 2, Burlington, Vt., set a record for its hottest overnight temperature as the thermometer refused to budge below 80 degrees Fahrenheit. Four days later, central Los Angeles hit 95 degrees before 11 a.m., already breaking the previous daily record of 94 degrees, before rising to well over 100 in the afternoon Nationwide, summer nights have warmed at nearly twice the rate of days, with overnight low temperatures increasing 1.4 degrees Fahrenheit per century since 1895, when national temperature records began, compared to a daytime high increase of 0.7 degrees per century. (Nights have warmed faster than days during other seasons, too.)