Regular temperature monitoring is the key to effective composting. Compost Temperatures indicate where the pile is in the decomposition process, and when the pile should be turned. As microorganisms work to decompose waste material, they generate heat. After a period of high temperatures in the "Active" and "Hot" zones, the pile temperature falls into the "steady" zone. This indicates that the pile should be turned and new oxygen is necessary to rejuvenate the decomposition process.