Measuring Large Compost Pile Temperature
The goal is for the tip of the thermometer to reach into the core or center of the compost pile. A composting thermometer made for this purpose is 36 to 48 inches long.
A compost pile can generate temperatures of 130-170 degrees, so a typical household (medical) thermometer will not be useful. Here is HGIC's fact sheet on composting: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG%2035%20Backyard%2...