Southwest Bike Path, Madison. A year ago the high was 81°F. Today it's 21°F. That's a swing of 60 degrees. The temperature has plummeted more than the sales of J. C. Penney, and that's saying something.
Global warming doesn't mean it gets steadily warmer year by year. Rather, the extra energy trapped in the atmosphere makes the weather more variable -- wilder swings in temperature, stronger and weirder winds, bigger storms. Along with a warming trend in average global temperatures, an average that smooths out wild swings here and there. Right now the Jet Stream has turned into a superhighway running straight from the Canadian Arctic right to our backyards. Never a dull moment.