Sesame (Sesamum indicum L.) is an economically important oilseed crops worldwide. Charcoal rot disease incited by Macrophomina phaseolina (Tassi) Goid. is one of the most destructive disease of sesame and causes heavy losses annually. Environmental factors play an important role for development of disease at different growth stages of the crop. Weather factors play a major role in activation, growth and multiplication of the pathogen and subsequently disease development. Time of pathogen attack and progression of disease in relation to prevailing weather conditions is necessary for prediction of disease occurrence and their management. Epidemiological studies showed the onset of charcoal rot varied in sesame varieties HT 1 during different dates of sowing. Among three dates of sowing, the maximum disease incidence was recorded in early sown crop followed by mid sown and minimum in late sown crop in consecutive two years. The quantitative relationship between charcoal rot disease progressions and weather factors on sesame varieties during different dates of sowing revealed that disease incidence was positively correlated with maximum temperature, evaporation and sunshine hours.