It's generally accepted that riding a bike in temperatures below freezing is too cold. When the temperature dips below 32 degrees Fahrenheit (0 degrees Celsius), water freezes and turns to ice. This can make riding a bike dangerous, as you could slip and fall on icy roads or trails. In addition, your body is more likely to be injured if you crash when it's cold outside. So if you're planning on cycling in colder weather, dress appropriately and be prepared for some slippery conditions.