This paper proposes the design and application of temperature sensor to free the stress of continuous check on the environment for any change in temperature. This can help in having an accurate reading of changes in temperature over a particular period of time. The instability in temperature of an environment (for example server rooms of data centers) can cause damage, and also reduce the efficiency and life span of equipments found in the data centers. An alert sub-system and a Global system for mobile communication (GSM) module was incorporated into the design to make it more effective. This environmental monitoring system was designed to monitor the temperature at certain range (either increase or decrease) and it is powered by an external source of power supply via an AC to DC power adapter