On a relatively nice spring or fall day with a temperature 50 degrees F, getting wet and being exposed to a 20 mph wind can be equal to a temperature of 32 degrees F. You will need to be dressed for freezing weather. Rain gear is effective as a barrier against both wet and windy conditions and should be a constant companion on any extended outing. In its simplest form, layering your clothing consists of 4 layers. The base layer next to your skin should be light and not capable of readily absorbing moisture. Any of the plastic based cloth materials commonly available, such as polypropylene, are excellent.
Moisture absorbing cotton is a poor choice.
The mid or insulating layer should be able to capture and hold air and also should allow moisture to pass through. The shell or outer layer should provide additional insulation and a moderate ability to block air. This will hold some of the undesirable moisture in, but is balanced by its wind blocking ability. The final layer is not always used, but is necessary when you do need it, and that is a rainproof layer. It can also double as a windproof layer and can not only keep you dry, but warm as well.