Don't worry, no mittens, coats or hats are required to read this post.
The deep freeze much of the country has experienced this past week (along with some areas in the rest of the world) is visualized by the NOAA in this new video. It's like seeing your breath on a freezing day, but on a massive scale:
Here's how the NOAA describes it:
A drop in the jet stream sent temperatures across the United States plummeting over the Martin Luther King Jr Holiday weekend. The pronounced change in temperatures can be seen in this weather data from NOAA/NCEP's Real-Time Mesoscale Analysis. Areas colored blue are below freezing. The diurnal cycle of heating and cooling can be seen over time, but the pattern is clear: much of the U.S. is pretty cold.