Obviously it is best to process ASAP after exposure but a few weeks in temperate climate isn't likely to cause a problem, certainly not with consumer C-41 which is designed to withstand this sort of thing. (I'm reminded of the stories about films brought in for development with pictures of a Christmas Tree on beginning and end, with summer holidays in the middle!)
I keep all my new films refrigerated or frozen in the manufacturer's sealed packing, but I've never fridged exposed film, having a concern that the damp atmosphere in the fridge (or even condensation) might penetrate the unsealed packing. I don't know if this a known issue?
Also, were your "summer films" exposed to any hot days while in the camera?