In this study, the monthly average minimum and maximum temperature meteorological data obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) during the period of thirty eight years (1979 – 2016) were used to estimate the mean velocity and most probable velocity of atomic Oxygen and Hydrogen for Ilorin. The values of the mean velocity and most probable velocity for these atoms were compared to the value of escape velocity. The results revealed that the highest values of mean velocity and most probable velocity for atomic Oxygen were found to be in the month of March with and respectively and the highest values of mean velocity and most probable velocity for atomic Hydrogen were found to be in the month of March with and respectively. Based on the values of the mean velocity and most probable velocity for atomic Oxygen and Hydrogen obtained during the studied period suggests that these atoms cannot escape the gravitational field as their values are less than the escape velocity .