Protecting outdoor stove

Six years ago I have made an outdoor 18-brick stove from red bricks. It was serving me well until now, bricks started to deteriorate.
I used an opportunity to get free scraps of firebricks from the neighbor and I have built a new one brick stove. It has been like assembling a puzzle since each piece of brick was different.
The stove works great anyway, and now I'm thinking to cover it with some kind of coat/plaster. I do not want to build any roof above it. I'm in cold temperate climate with pretty cold winters but I still use this stove with snow lying around. When not in use, the top of the stove is always covered with a big metal bowl.
My question is - what can I use as a plaster to protect the bricks from the elements?

I suspect your red brick stove wore out from thermal cycling, not weathering.
Firebricks are far more durable in this regard.
Any plastering would have to endure thermal expansion/contraction  and weathering as well or better than the firebricks.
How about a high temperature refractory cement with mineral wool fibers added to resist cracking?

I would stick with the bowl, get an even bigger bowl or maybe add a tarp or sheet metal.