We live in Everett, WA, my tools are in storage in Lake Stevens, WA. Add to this we live on the water.
The best option is, and this will depend on the size of your shop, put a oil radiator heater in the shop, may two depending on size. Then add one or two box fans.
The constant air movement will dry the air faster and better than any heat will ever do it. In fact, too much heat will only create a wider differential between the air and your equipment condensing the water from the air.
I spray my lathe and other tools down with WD40 on a regular basis. The floor in our storage unit is radiant and is only high enough to keep the worst conditions from forming.
I have never tried it, but I wonder how well radiant heat would work. It would keep the machines warmer than the dew point and should prevent condensing process.