A supercell system walloped much of northeast Illinois and northwest Indiana on Monday night.

Chicago isn’t likely to break the 35-year-old record high of 99 degrees set for June 14 back in 1987, even though the heat index is expected to top 105 degrees. Which begs the question: What is the heat index?

Mild temperatures will give way to blistering heat this week, with the National Weather Service warning of temperatures in the mid-90s and peak heat indices of 110 degrees on Tuesday and Wednesday.

A new study concludes that Cook County has become one of the most desirable places for those escaping the extreme effects of climate change. Climate refugees seeking more stable environments look to cities across the Midwest. But is the Midwest really a safe haven? 

Power operators in the Central US, in their summer readiness report, have already predicted “insufficient firm resources to cover summer peak forecasts.” That assessment accounted for historical weather and the latest NOAA outlook that projects for more extreme weather this summer.

The combination of high temperatures and humidity sent heat indices soaring above 100 degrees Wednesday. Thursday will see more of the same.

Anchored a mile off Navy Pier, Chuoy the Buoy fills a Chicago-sized gap in shoreline monitoring. Swimmers, boaters, anglers, researchers and meteorologists alike will benefit from data collected close to the city’s lakefront.   

April was the rollercoaster ride, weather-wise, Chicagoans have come to expect from spring's most capricious month.

Pennsylvania on Saturday becomes the first major fossil fuel-producing state in the U.S. to adopt a carbon pricing policy to address climate change. It joins 11 states where coal, oil and natural gas power plants must buy credits for every ton of carbon dioxide they emit.

For the hundreds of thousands of Chicago Public Schools students kicking off their spring break Friday, it’ll look more like a snow day.

Methane is a big contributor to climate change, leading to about a 0.9 degrees Fahrenheit (0.5 degrees Celsius) increase in temperature since the 19th century, according to the Intergovernmental Panel on Climate Change. Carbon dioxide has caused about 50% more warming than methane.

Scientists say global emissions need to drop 45% by the end of the decade compared to 1990 levels. But recent data show they are going up, not down, in part due to rising energy demand and the expansion of fossil fuel use.

The weekend will kick off with subzero wind chills Friday night into Saturday morning, before milder temperatures move in Sunday, forecasters said.

A powerful line of thunderstorms ripped through the Chicago region Saturday night, with wind gusts topping 80 miles per hour. The wild weather continues Sunday with winter mounting a comeback.

Get ready to experience spring, a brief dalliance with summer, and then a return to winter – all in the coming weekend.

An expected snow-making weather system took a swing south, downgrading anticipated accumulation in the Chicago area, according to the National Weather Service. The evening commute could still be messy.