Cyclo-Cross is traditionally a winter form of cycle sport. It usually takes place on grass playing fields or parks but will often take in tracks and trails of all conditions.
You will normally ride a Cyclo-Cross on a specific bike which will look like a road bike with drop handlebars but will have knobbly tyres and extra clearance for the wheels. Brakes will either be cantilever or disc brakes. You can normally also ride Cyclo-Cross on a mountain bike (e.g. a 29er is good).
The season normally runs from about September to January.