Populations of the house fly,Musca domesticaL., and other filth flies and their natural enemies in confined-animal houses are greatly influenced by the temperature of their manure habitat. In order to use filth fly management simulation models that are driven by habitat temperatures, a mathematical relationship between manure temperature and air temperature, time of day, and manure depth was developed based on simultaneous hourly measurements of air and manure temperatures at depths of 1, 7, and 15 cm in three poultry housing environments over a three year period. Manure moisture had no measurable effect on manure temperature. A simulation model predicting population sizes of the house fly and a predaceous mite was driven using temperatures from the equation, and actual air and manure temperature recordings. Predicted population sizes using the estimated manure temperatures were closer to the sizes using actual manure temperatures than the sizes using air temperatures.