It's a funny thing about washes. Even though they look dry they are, in reality, water ways. Sometimes water is flowing not too far below the surface. What does that have to do with anything? When you're on a bike you feel the cold. Due to the moisture found in the washes, the temperature around the wash can drop a good ten degrees or more. You feel it.
I laid out some winter riding clothes and I'll go dig out my full-finger gloves before bed. I'm already wondering what the heck I'm thinking but I suppose this actually holds true to form--I'm a glutton for punishment.