Hi Peter!
For the most part, the WSM needs no mods for winter cooking. I have smoked during Packer games in December and January and smoked thru blizzards a few times and have only needed to make a few adjustments, mainly to my fire starting technique.
Here are the things I do differently when the temp dips below 30?.....
I will use more lit briqs when using the Minion method. This is not an exact science, but you will get the hang of it pretty quickly. A full chimney is called for when windy AND cold.
I will also let the smoker come up to temp first. Normally, I put the meat on immediately following dumping the lit briqs in. In the winter, I like to see the pit reach my 225-250? level first.
If really cold, I don't use the water pan OR I boil the water first when the weather is borderline.
Also, I avoid overloading the cooking chamber.....NO 10 racks of ribs or 4, 8lb. butts or briskets!
As you will find out, the wind is the biggest problem, not the temperature outside. So, perhaps a wind shelter or moving it partially inside is what you will need to do.
You will also find that smoking during blizzards is harmful to your thermometers!
