What to Wear
Be always aware of the weather where you are going. It could be sunny and toasty where you are but rainy and cold where you are going.
During winter wear warm clothes but not too much. Your priority is to stay warm. But, If you are warm and comfortable before starting to ride, you are wearing too much. As your body temperature will increase when you start working out and you will overheat, you should start just a little bit cold. Always bring a windbreaker to wear for downhill.
If you go for a ride with chance of rain bring your rain gear just in case. Remember that if you feel cold when you are riding it will be worse if you stop, so keep moving.
In summer avoid riding at the hottest time of the day. Best to ride early in the morning or at the end of the afternoon. Avoid dark color for your gear — prefer white, even for your helmet.