Layering allows you to change the amount of insulation you need depending on how your activity level and the climate change. Wearing too little is an obvious problem, but if you wear too much, you’ll sweat significantly, which is not only uncomfortable, but can make you dangerously cold when conditions change.

In cold weather, you’ll probably want to use at least two of the following layers:

• Wicking base layer - keeps sweat from getting trapped next to your skin. This helps perspiration evaporate when you’re hot, and keeps you warmer when you cool down and don’t want to be wet. Ideally, it should not lose its insulating properties when wet. Wool, polyester, polypropylene, fleece, silk, and other materials used for winter sports work well. Avoid cotton - it keeps sweat close to your skin, becomes a lousy insulator when wet, and take a long time to dry out.
• Insulating layer - often fleece, wool, or other fluffy air-filled material.
• Shell - repels water and protects you from cold wind. Outer garments are often ventilated in the back to allow cooling where direct blasts of wind or rain is not a problem. Nylon, neoprene, plastic, and rubber are common materials.

Experience is the best way to determine the right number of layers for the weather. It’s best to start most cold-weather rides feeling somewhat chilly, but not very cold, and allow yourself to warm up to a steady temperature during your first mile. Remove a layer as soon as you start to feel like you might get too warm. If you’re still cold after a mile or so, add a layer. If you can’t add enough layers to get warm, seek shelter.

If your ride is very short, e.g. a mile or two for transportation purposes, and your priority is comfort, go ahead and dress warmly from the start, and regulate your temperature by regulating your pedaling effort or removing layers.

A rack-mounted cycling bag is very useful for storing additional or discarded layers as you ride, especially for longer trips or when experimenting with cold-weather clothing. For thin layers, a jersey pocket may be large enough for storage.

Never try to ride long distances in the cold without extra layers for emergencies. If you have a mechanical or physical problem, your body temperature can drop fast when you stop. Try to stay near civilization, and be prepared to phone for help if something goes wrong. Most importantly, never go cycling alone in isolated areas (such as seldom-used mountain bike trails) in very cold weather. If you become injured or immobile, you may not be able to get help in time. And of course, you can never have enough spare inner tubes….or matches.

• Insulated pack
• Metal pan/cup for melting snow (on those long, extreme rides - just in case)

• Bag for storing clothing layers and emergency equipment
• Tool kit/patch kit/pump/spare tube
• Matches (for those long, extreme rides)
• Lights for shorter days
• Mobile phone/radio (or other plan to make emergency calls)
• Platform pedals to accommodate boots, fast foot-downs on ice and snow
• Knobby or studded tires for ice and snow (front wheel most important)
• Lip balm, sunscreen (for long rides in snow - snow reflects UV rays)

The ICEBIKE web site - for those determined to let nothing stop them from riding. Great info:

http://www.enteract.com/~icebike/

Winter cycling class:

http://www.bikewinter.org/bwclasshtml.html

Affordable clothing solutions for the practical winter cyclist:

http://www.bikewinter.org/cmbighorn.html

Metal-studded tires are ideal on ice and hard-packed snow. Knobby MTB tires are also acceptable, and do well on shallow snow. Slicks should only be avoided if there is significant ice or snow on the road. Center-slick side-knobby tires allow safer turns but do not brake or accelerate well on snow or ice.

Platform pedals allow you to put your foot down fast if you slip. Wear boots; cycling shoes and clipless pedals don’t work well when you’ve been walking in snow.

Black Ice is a thin layer ice covering the road - it looks like a wet pavement. It is usually found where rain or melted snow has frozen due to falling temperatures. Avoid it if you can. If you must ride over black ice, do the following:

• Slow down before you get to the ice.
• Ride straight and coast across it. Avoid turning, braking, or cranking.
• If the ice patch is large and/or on a hill, and your tires aren’t studded, dismount and walk.

Textured ice and ice/snow mixtures make for unpredictable riding. Go slow, but braking and steering will be better then on a smooth sheet of ice.

Packed or shallow snow is often easier for maintaining control than ice, assuming the top surface has not glazed over. Be gentle with braking and turns. Knobby tires are all you need for these conditions. This can be a lot of fun, but be careful to avoid places where stumps, roots, and other hazards may be hidden under the surface of soft, loose snow.

Deep snow will give you quite a workout, or stop you in your tracks. How hard-core are you?

If your front tire suddenly slides sideways: Put your foot down on the side your body tips. Your foot will slide along the ice, and you now have three points of contact with the ground. Steer the front wheel slightly toward your tip direction to bring the bike back underneath you. Do not turn it too sharply or it will just slide, or may grab and throw you over the other side of the bike. When the bike begins to return, replace your foot.

If you are braking and your back tire slides sideways: Steer in the direction of the skid while reducing both front and rear braking. If you tip too far to stay on the bike, put your foot down and let it slide as a tripod until you regain control of the wheels.

Be careful where you stop and dismount. Try to find bare pavement or a surface with good traction properties before you put your feet down.