I have used the smoker in the middle of MN winter no problem.  I clean the whole thing after every smoke session.  Burner now will not stay lit.  Will not be buying this brand again.  I have disassembled and cleaned the burner assembly, no change.  The guts of this thing need to be replaced after 4 uses.  Checking BBQ forums throughout the internet provide the same problem with many users.  DO NOT BUY MASTERBUILT!