In the upper Midwest, it gets cold in the winter. I mean cold as in temperatures regularly don't get above freezing from late November to March. And, here in Minnesota, we tend to get lots of snow. Last winter we accumulated 84.6 inches (that's a little more than seven feet) of snow, our fifth snowiest on record.
With this kind of weather, it can really put a damper on riding. The latest issue of Bicycling printed a guide to make it easy for those of us who don't often ride when it gets below freezing. This is it, reproduced for you:
65-70: START WITH Base layer; short-sleeve jersey; short-finger gloves; socks
60-65: ADD Arm warmers; full-finger gloves
55-60: SWAP IN Knickers or knee warmers; thicker socks
50-55: SWAP IN Leg warmers ADD Vest
45-50: SWAP IN Thicker gloves; long-sleeve jersey ADD Toe covers; a sock layer; ear-covers (comfort over style)
40-45: SWAP IN Tights; long-sleeve base layer; thin hat (you might have to loosen your helmet)
35-40: SWAP IN Shoe covers or winter cycling shoes; thick hat or balaclava
30-35: SWAP IN Heavier tights; lobster gloves or mittens
25-30: ADD Second long-sleeve jersey; mid-layer sock
25 and below: ADD Base layer short and/or knee warmers under tights
Keep in mind that this isn't the gospel and you may need to modify what you wear if it's windy or precipitating, or if you tend to run hot or cold.
There are also a few "clothing calculators" to help you figure out what to wear when the mercury dips. Check out Bicycling and Castelli's what to wear on VeloNews.com.
Until next time, ride long and keep the rubber-side down.