Can I use my kamado when its freezing?

Even when it's freezing you can use your kamado!

But make sure that you let the temperature rise as slowly as possible, especially if it is cold and/or damp weather. This allows the ceramic to settle and prevents cracks and/or cracking of the ceramic.

To allow the temperature to rise slowly, start with the top and bottom vents that are only open for a small part. You can slowly open them further and further to let the temperature rise. So be patient. 

Do you use a rain cover? Great! This protects your kamado against rain and dirt, but not against frost.