All you need to do is change spark plugs between summer and winter.
For example here in the desert I run a BPR7HIX in the summer, a BPR6HIX in the winter.
The 6 and 7 are the heat index number.
The higher the number the more heat the plug transfers to the head.
If your engine just doesn't want to warm up well, lower the number.
Look at the size difference in the white insulator length where the plug threads are.
The more white you have in contact where the threads are, the more heat is transferred to the cooling fins, and the pink is just providing an air gap to keep heat in.