You'll get toasty hot when you're fighting snow and mud. But when you get to a fast downhill, you'll freeze. It's best to layer so you can adjust your protection. I use fleece-lined tights worn over a standard lycra biking short. I wear the short because, (1) if I get hot, I can strip and dump the tights in my CamelBak, (2) I can drop the mud-covered tights and shoes on the porch, and go into the house clean, and (3) on a fast downhill, a sweaty crotch can cool down VERY quickly if there's only one layer. I wear a standard bike jersey over a very thin wool-acrylic long-sleeved upper body tight. I'm OK down to 20 degrees. If I'll be doing some fast downhill, or if there's a nippy wind, I add a nylon shell (1-layer, no insulation).

A thin earband will keep your ears from freezing on the downhill. I have it in the back pocket of my jersey on the way up.Long-fingered with a thicker fabric and leather will do for short warm rides. If you'll be downhilling much, use ski gloves or heavy winter cycling gloves. If you put bar-mitts on your bike, you can ride with light summer gloves.Toe spikes are highly recommended. Most days, you can use your summer shoes with double-socks. (Be sure to use wool-acrylic socks, NOT cotton. Cotton is your enemy in the winter.) You can buy shoe covers that keep the water and wind out of your shoe. These covers have a hole in the bottom for your cleat. High-top winter bike shoes are waterproof and have extra padding, but cost they can be pricey. But if you find yourself riding regularly in the winter, buy them!

In the winter, I swap my small light SPD pedals for downhill pedals (where a pop-up binding is surrounded by a toothed cage). If my cleat and pedal become packed with ice, I can still stand on the platform and ride with confidence.

If you go "digging" on wet four-wheel drive routes with your bike, you'll find mud. Mud destroys standard brake pads and rims. You may want to go with a softer brake pad -- to compensate for the cold, and to reduce the sandpaper effect on your rims. (I wore right through an expensive set of rims in one year!) You'll need to tune and adjust your brakes more frequently, preferably before every ride. (Winter biking is where disc brakes are worth the money. They perform like a charm!)

You may think St. George is warm because there's no snow. But if you're making an epic ride such as the Stucki Springs loop, you'd better pack hypothermia gear. You WILL die if you spend a winter's night in the desert unprepared.

You may find a hard-packed snowmobile or ATC trail in the high mountains, but in general, most winter biking is at low altitude. Just about any trail can be ridden with 4 inches of soft snow. Once it reaches 6, the uphill will be a battle. Trails we've ridden during every month of the winter: Bonneville Shoreline SLC north and south, Corner Canyon's Potato Hill-BST-Canyon Hollow-Ann's loop, Hog Hollow, Alpine's Lambert Park, Antelope Island, Stansbury Island Mountain.

Winter riding requires a strong biker with a steady, light touch. Abrupt moves may break through the crust on the snow, or skid the bike into the deep snow on the edge of the trail. Sudden force on the pedals can make the rear tire break loose and spin. Keep the effort smooth and consistent. It helps to be locked onto the pedals -- avoid putting your feet down in the snow, or pretty soon there'll be a sheet of ice covering your cleats.

Chain-suck on a mud-ride can be a big problem. (This is where your muddy chain sticks to the small front chain-ring and rides up until it gets stuck against the other half of the chain at the top of the ring.) In general, I've found chain-wax to be more resistant to chain-suck than oil. It's also easier to clean a waxed chain with snow or mud-puddle water on the trail.

I keep a very short hose on the south side of my house. I use it to forcefully spray off my bike after muddy rides, with extra time and water pressure applied to the chain and pulleys. Watch which direction you're spraying -- don't force mud into the cable ends or shock absorber boots! After washing the bike, I blow the water out of the hose and disconnect it from the faucet (to avoid freeze damage).

You'll need to clean the chain after every mud ride. Not just a rinse; a high-pressure cleaning. Chain wax lets you get the chain cleaner than oil lubricants. I never use oil lube on my chain any more. Any oily dirt that remains in the chain acts like "grinding compound." If there's no sunshine, I blow-dry the chain. (If you use chain wax rather than oil, you have increased rust risk. Your chain can form rust in just a few hours in the garage.) I re-lube when the chain is dry, before putting the bike away for the day.