Climate Change on Rampage: Chicago Experience Historical Heat Index That Feels Like 120 Degrees

This summer has claimed over 500 lives in Chicago due to extreme heat wave.

Chicago’s climate, known as "humid continental," by Koppen climate classification system exhibits a wide seasonal temperature contrasts. It experience extreme hot summers and cold winters. According to Encyclopedia Britannica, this condition persist "between 30° and 60° N in central and eastern North America and Asia in the major zone of conflict between polar and tropical air masses."

The previous high temperature in Chicago was 97° in Aug. 23, 1947. The earlier record of heat index was 116 in 1995, which is also broken this year. Meanwhile, actual temperature hit 100°C at O'Hare at 3 p.m. on last Wednesday, which is recorded hottest since July 6, 2012 (103°C).

Historic heat index in Chicago:

According to NWS data, "a temperature of 98 degrees was measured at O’Hare International Airport, which would make it the hottest Aug. 23 on record in the city of Chicago."

O’Hare also measured "a heat index of 116 degrees, the second-warmest heat index ever recorded at the airport."

"In other parts of the area though, things felt even hotter. In Morris, located in Grundy County, temperatures hit only 95 degrees, but the heat index measured at 124 degrees," according to officials.

What is Heat index?

Heat index is the measurement of human body condition, due to combined impact of humidity and air temperatures.

As per definition: "The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature."

The human body, generally feels more warmer in humid surroundings. The opposite is also true when the relative humidity starts decreasing due to the increase in the rate of perspiration. Scientifically, the human body feels much cooler in arid environment. Meanwhile, there is direct connection between the air temperature, relative humidity and the heat index. In other words, with the increase in air temperature and relative humidity, the heat index also increases and vice versa.

"Due to an intense heat wave across the Midwest and through the South sent heat index values skyrocketing well into the triple digits this week, as 98 million people remained under heat alerts," according to NWS data.

Have a look on the heat wave in a real time data

According to the NWS data, here's a complete list of heat index values across the area on the last Wednesday:

Chicago-Midway: 117

Chicago-O'Hare: 112

DeKalb: 109

Joliet: 115

Kankakee: 113

Morris: 120

Pontiac: 113

Rantoul: 112

Rensselaer, IN: 108

Rockford: 110

Rochelle: 112

Sugar Grove: 117

Waukegan: 112

West Chicago: 110

Wheeling: 112

Valparaiso, IN: 108

What is the reason behind this extreme heat wave?

The reason behind such extremely high heat index is the shape of the place and region. The heat wave is mainly caused by a 'heat dome'. This is actually a ridge of high pressure, that stalled over the central U.S.A.. This shape traps the hot air over the region leading to a rise in heat index.

As per few recent studies, Solar energy became four times higher in Chicago’s latitude in early summer. This raised solar energy made summers extremely hotter.

Solar energy doesn't get spread evenly on the earth surface. Scientifically, cooler air is more denser than warmer air, this leads to cooler air to fill less-dense areas of warmer air creating wind. This is exactly what happens in Chicago during summer.

"I haven’t been to hell, but I say this has got to be close," Demetrius Gee, a resident of Chicago told. Extreme heat is the clearest signs of climate change. Eventually, it is becoming more frequent and intense, majorly due to anthropogenic activities.