Dallas Sets Record: 70 Days Above 100 Degrees | The temperature at Dallas/Fort Worth International Airport rose to 106°F today, the 70th day the city hit 100 degrees this year. “The previous record for number of 100-degree days in a year was 69, set in 1980,” the Wall Street Journal reports. Texas had the hottest summer of any state in United States history, with an average state-wide temperature of 86.8 degrees in June, July and August. County health departments in the Dallas-Fort Worth area have reported 23 heat-related deaths and hundreds of cases of illnesses brought on by high temperatures. By the end of the century, Dallas will have more than 100 days of 100-degree weather every year because of greenhouse pollution.