An apparatus for monitoring environmental conditions favorable for mold, mildew and fungus growth includes a microprocessor having a data map, a temperature sensor attached to the microprocessor, a relative humidity sensor attached to the microprocessor, an indicator array attached to the microprocessor, and a power supply attached to the microprocessor. The map has a plurality of relative humidity and temperature combinations and one or more suggested actions, for the user, based on the combinations. The indicator array may be a single warning light or an array with a plurality of warning lights. The indicator array may also be a text display or an audio speaker for displaying one or more ambient conditions or suggested actions. Barometric pressure data may also be included with the map for more comprehensive suggestions for action.