ZAP! Why is Winter Static Season?

We're fast approaching what are usually the coldest, driest months of the year (at least here in the northern hemisphere), and with that comes the annoying tendency of doorknobs to shock and startle us whenever they're touched. It happens to some extent almost everywhere, but it wasn't until I spent a week at a conference in Montana--and found myself flinching every time I had to press the elevator button--that I really gave some thought to this usually-minor annoyance.Static electric charge acc...