A milk temperature monitor helps determine the health or physiological condition of a lactating animal (e.g., cow, goat, sheep, camel, etc.). It does this by comparing the temperature of the animal's milk to an acceptable temperature range that is automatically adjusted to compensate for a varying ambient air temperature. In some embodiments, the acceptable temperature range is adjusted based on the average milk temperature reading of the most recent series of animals that were milked. The average reading is preferably a rolling average of a limited sample size. In calculating the rolling average, the monitor disregards temperature readings that are beyond a reasonable range. The monitor can record and display historical peak temperatures rather than real-time temperatures. In some cases, the monitor's microprocessor and power supply are hermetically encapsulated within a clear permanent cast housing. Proximity switches within the housing provide a means for inputting user-selectable parameters into the microprocessor.