Dress for success on the bike
There is a simple rule for dressing for Spring and Fall on the bike: arm warmers and knee warmers for racing; long sleeves and leg warmers for training.
As an endurance athlete, your body can perform best if it doesn't have to spend energy keeping you warm while training. So, bundle up! If you have ever seen pros out riding in even relatively warm weather, you will notice that they are always covered up. Part of this is because they are whippet-skinny, but it is mostly because this way their muscles can concentrate on propelling them forward (and getting better at it) instead of shivering to keep them warm.
The magic number is 65 degrees (18 degrees C). Below that, wear long sleeves and leg warmers while training. If you sweat a bit, that's okay - just make sure you wear a light moisture-wicking base layer. When it gets colder, add a cap and a vest.
Now you know how to dress like a pro!