If you are going to change the oil then before hibernation is the time to do it. The main issue with oil is becoming contaminated with combustion products so best to get rid of these before the engine stands idle for some time. If you want to be really careful then warm up the old oil, drain, refill and circulate oil on the starter without starting the engine. This may, however, all be a bit OTT if your oil is not very old to start with.