Officially at O'Hare right now it's 15.6°C, down slightly from the 16.1°C recorded earlier. My car says it's 17.5°C. These temperatures would be normal for late April or mid-October.
The forecast calls for temperatures to drop to a more-normal -1°C by next weekend, but after that the CPC forecast calls for a 75-90% probability of above-normal temperatures through March.
Keep in mind, warm winters in Chicago often lead to warm summers, because the lake can't dissipate as much heat as it does in a cold winter. And as we're seeing this year, summer temperatures have little influence on winter temperatures here. So while we're all excited about a warm winter, we need to keep in mind that next summer could be brutal.
Forecasters predicted that this year's El Niño would lead to a warm winter, but they weren't really sure. It looks like it will.