2024 set to be Chicago's warmest year on record

Chicago is set to have its warmest year on record, beating the previous benchmark set in 2012, according to the National Weather Service.

Based on preliminary data, Chicago's average temperature for 2024 is on track to be between 54.8 and 55.0 degrees, breaking the previous record of an average of 54.5 degrees in 2012, the weather service said. Prior to that, the previous year average record was 54.4 degrees set in 1921.

Official numbers for 2024 will be released on or just after Jan. 1.

National Weather Service meteorologist Gino Izzi cited climate change and a fall drought as factors behind the high temps, which allowed for greater temperature fluctuations. Air is easier to heat and cool than water, so less moisture meant bigger jumps in temperature throughout the day.

This also exacerbated Chicago’s higher night temperatures caused by heat dissipating off the “concrete jungle,” Izzi said.

“It's a very unique situation,” Izzi said. “When conditions are really dry, temperatures more quickly fluctuate. … That allowed temperature swings to be more drastic.”

Five months of the year were in the top 10 warmest on record; February set a new record with an average of 39.5 degrees — beating the previous 1882 record of 39 degrees — and September was the second warmest on record, averaging 70.6 degrees, less than a degree shy of the 1931 record.

And Chicago isn't alone. Rockford is also set to have one of its top five warmest years on record, ending with an average between 52 and 53.1 degrees. If temperatures close out the year higher, it could beat records set in 1921 and 1931, and on the lower end would top a 2021 record.

The pattern extends beyond months, as the last several years have also seen record-breaking averages, which Izzi said is more attributable to climate change than single-year outliers, which can be influenced by things like droughts.

“That’s a 152-year period of record, and in the last 11 years, five of them have been the top 10 warmest,” Izzi said.

Looking at the year ahead, Izzi said another record year of tornadoes wouldn’t be surprising — it has been broken two years in a row — but that was more due to advancements in technology that allows the NWS to retroactively document tornadoes. The tornadoes seen in and near the city have had longer paths, though, which is a change caused by climate factors.

For the near future, Izzi said Chicagoans can expect a drier January with a possibility for “closer to or below average” temperatures, though snow may spring up toward the end of the month.

“There will still be cold periods mixed in,” Izzi said. “But on the whole, climate change is making it easier for warmer conditions to happen more often.”