03' yz250 rear suspension slow on rebound?

[jerry and sons]

I purchased a used yz 250 and I am new to dirt bikes, so please excuse my ignorance. I have been riding the bike for a few months now and everything has been fine, but today was in the high 40's and low 50's (degrees) and it seemed that the rear supension was slow on the rebound. Is this because of the temp or is there another problem going on here?

 

[minutz]

My guess would be the linkage or swing arm bearings, they need to be taken apart, cleaned and regreased or replaced. Remove the shock and see if the swingarm moves freely up and down with no side to side movement.