Thursday August 9 was the first day with a below normal daily temperature at Chicago's O'hare International Airport since June 26. The high on August 9 was 75 with a low of 63 yeilding an average of 69. That was 4 degrees cooler than the normal of 73. The last below normal day in Chicago was June 26 when the high was 83, the low was 56, and the average was 70, which was 2 degrees below normal. Thursday's high of 75 also broke a string of 44 consecutive days in Chicago with a maximum tmeperature of 80 degrees or higher. It was the second longest stretch of 80 degree weather, following 46 straight days in 2010. Chicago temperature records go back to 1871.
For Rockford, the high was 74 on Thursday August 9. This was the first time the temperature failed to reach 80 in Rockford since June 13, when the high was 76. Rockford had 56 straight days with a maximum temperature of 80 degrees or higher. This tied 1921 for the second longest stretch of 80 degree weather in Rockford. There were 58 days in 1936. Rockford data goes back to 1906. There were 86 straight days of 80 degree weather in 1895 but Rockford data is incomplete before 1906.