Temperature will be the easiest indicator to monitor. Compost thermometers with over 12” probes are available for under $20. When a human hand can be placed into the pile and not burned, the temperature is below 130F. When a hand cannot be held in the pile for longer than a few seconds, the temperature is above the 130F mark. Temperature above 160F is not desired because certain beneficial bacteria are lost. The location in the pile will influence the temperature. Normally it is recommended to test the internal temperature, about 2/3rd down and 1/3rd in from the side. The hottest spot in a windrow will be the top of the pile where convection currents exit the pile. This is the place to check for excessive heating. Figure 1 on the last page provides some ideas of how temperature patterns are influenced by the C:N ratio.