Originally Posted by KonaRider24
The only time a longsleeve is ok for xc is if it's cold out or if it's a wet sloppy mess out, and in those conditions, it is best to not ride in the first place. You will look like a fool in any other condition out there.
Or if you happen to be riding in northern California where there is a TON of poison oak. NoF3ar, this includes where you are - if you react to poison oak, I would ride with long sleeves (and most folks around here do), and would use Tecnu right after a ride to get the poison oak oil off of your skin.
The long sleves are a layer of protection from keeping those damn leaves off of you.