Hey, Walter!
I am a contractor and we also sell products to other contractors. If you want to stick to an oil sealer during the winter months, I highly recommend using sealers that are 100% parafinnic oil (no linseed). We use Ready Seal, which has no temperature limit. The only trick to using Ready Seal is that wood must be dry (under 15% moisture, with 12% recommended by manufacturer). They also offer a special formula for redwood to keep the tannins in check. This stuff saoks in to the wood in about 15 minutes, and it can be walked on or rained on immediately without any problem. Georgia weather is touchy over the winter months (sometimes takes a long time for the wood to dry) but we have been able to seal every month for the last four years (since switching to this sealer). Good luck!