From NCDC: The blistering heat experienced by the nation during August, as well as the June through August months, marks the second warmest meteorological summer (June 1 - August 31) on record according to scientists at NOAA’s National Climatic Data Center (NCDC) in Asheville, N.C. The persistent heat, combined with below-average precipitation across the southern U.S. during August and the three summer months, continued a record-breaking drought across the region.
The average U.S. temperature in August was 75.7 degrees F, which is 3.0 degrees above the long-term (1901-2000) average, while the summertime temperature was 74.5 degrees F, which is 2.4 degrees above average. The warmest August on record for the contiguous United States was 75.8 degrees F in 1983, while its warmest summer on record at 74.6 degrees F occurred in 1936.
Lincoln had five days with 100 F or higher temperatures, 4 at exactly 100 F and one day at 104 F. Note the white dots on the map indicate 1 to 10 days with temperatures reaching 100 F or higher.