Clothing

No Cotton, ever.

Bike Jersey

Bike Shorts (baggie shorts or lycra with chamois... this is not a time to wear cotton 'roos)

Socks

Shoes (flats, or with cleat compatibility for clipless pedals)

Helmet (properly fit; no cracks or previous crashes)

Gloves (long fingered are more versatile during cold weather)

Glasses (swappable light and dark lenses)

Wind Jacket (lightweight)

Rain Jacket* (can be same as wind jacket)

Head band* (keeps ears warm)

Wind vest* (keeps chest warm)

Arm warmers*

Knee warmers*

Tights*

* Optional item, or depends on weather... we often see wind-chill conditions on Mt Diablo with temperatures in the 20's