Northern Hemisphere, now is the time to go through all those coats, sweaters, scarves, mittens, boots, etc. and decide what you're going to wear within the next 30 days.
If it doesn't make the cut, get rid of it. Someone else needs it more than you need to maintain the Museum Of Unwanted Winterwear.
Southern Hemisphere, as above, but bathing suits, shorts, lightweight dresses, halter tops, sandals, and t-shirts.