Galactic cosmic rays are the high-energy particles that stream into our solar system from distant corners of our Galaxy. The Earth's atmosphere serves as an ideal detector for the high energy cosmic rays which interact with the air molecule nuclei causing propagation of extensive air showers. The primary cosmic ray particles interact with the molecules in the atmosphere and produce showers of secondary particles (mainly pions) at about 15 km altitude. These pions decay into muons which are the dominant particles of radiation (about 80%) at the surface of the Earth. In recent years, there are growing interests in the applications of the cosmic ray measurements such as space/earth weather monitoring, homeland security activities based on the cosmic ray muon tomography, radiation effects on health via air travel, etc. A simulation program (based on the Geant4 software package developed at CERN) has been developed at Georgia State University for studying cosmic ray showers in the atmosphere. The results of this simulation study will provide unprecedented knowledge of geo-position-dependent cosmic ray shower profiles and will significantly advance cosmic ray applications. Simulation results are critically important for determining the temperature coefficients in every pressure layer in the atmosphere in order to calculate the temperature variations using the cosmic ray data. Using a single particle shower simulation, the weighted particle altitude distributions on a global scale are calculated with geomagnetic field implementation. The results of the simulation can aid the computation of the effective temperature in stratosphere.