Winter Bike To Work Day is tomorrow, January 20 in Boulder, Colorado, where the weather will be a pleasant 30 degrees or so with partly cloudy skies in the morning.
Chicago also will hold BTWD on Wednesday.
Toronto does a Coldest Day of the Year Ride on January 30. That is statistically the coldest day of the year in Toronto.
For winter bicycling inspiration, see Streetblog's gallery of winter cycling photos posted last Friday.