Delta T is an important indicator to evaluate conditions suitable for spraying in agricultural and horticultural crops. Delta T is the difference between the wet bulb temperature and the dry bulb temperature. This mobile application calculates the Delta T value for the given temperature and relative humidity for farmers to easily calculate it without needing dry and wet bulb thermometers. The wet bulb temperature is calculated from the value of relative humidity. This App is in four languages, viz., Hindi, English, Bengali and Marathi.