It all depends on geography, quite frankly, and where you are in the world. If you live in an area that does not experience below freezing climates at any point then you can compost non-stop, all year round. The same can’t be said for folks who live through colder winters as the rate of decomposition is going to slow down exponentially. In this case, the compost pile may freeze over. Then again, the same pile will be fine once the weather warms back up (if you keep adding scraps).