Just to add. It was -22c here last night I started a shoulder in my wsm it held 225 exactly. Then I turned it up to 275 around 4am started the cook at 8 the previous night. It held 275 till 8 am no prob. 1 basket of coal didn't add at all.
Backwoods party,22.5 wsm,18.5 wsm,14.5 wsm, smokey joe, performer,22.5 kettle.