It was really really cold in Chicago in the past couple of days. Air temperature on Monday was -13°F (-25°C), and windchill was -40°F (-40°C). Chicago river, at least for the part that is connected to Lake Michigan, which normally don't freeze over was frozen.
Today it warmed back up to something closer to normal, 11°F (-12°C). It's amazing that how our bodies adjust. After a couple of sub zero (I am talking in °F, not °C), now single digit temperature actually feels warm. So, it is almost like a heat wave now that we are having temperature in the teens.
I heard that this weekend we will be in the 30's (above freezing). I guess it is going to feel like it is summer!