Temperature Variation

Wondering if any of you ever see this. This morning (5:00 a.m.) I check my stove (Alaska Stoker), The temp on the front of the stove is a little over 500 degrees. I come home from work this afternoon and check it , and it's around 425. This stove is not on a thermostat or anything. I set it and leave it go. It usually averages around 450 give or take 10 degrees. Do you think it could be the coal? I don't see any other reason it would do this. What do ya think?

If you just got a new load of coal, I would suspect that the coal is the culprit.

Depends on the outside temp, If it's really cold, it will draw better and probably heat up more, then it warms up and the stove runs a bit cooler. I have notice a bit more coal cakes, small clinkers since its been below 10-15 degrees at night, and I haven't changed anything in the stove or changed coal.