Estimation of Temperature – Humidity Index in Some Selected

Heat Index describes the combined effect of temperature and humidity on human body. The heat index renders an apparent temperature felt by human body that cools slower at higher values of the relative humidity due to thereduction of the evaporation rate. This study was aimed at describing the temperature-humidity index (THI) over Nigeria. The THI was calculated by using monthly mean values of temperature and humidity obtained from the National Aeronautics and Space Administration (NASA). The results show upward trend of THI in all the regions of Nigeria between December and May. The highest value of THI of 31.3oC has been observed in Maiduguri in May. Forecasting performance parameters such as root mean square error (RMSE), mean bias error (MBE) and mean absolute percentage error (MPE) are presented as analyzed for the National Weather Service (NWS) and the Schoen models. The results show that the Schoen model compared statistically favourably with the NWS. The Schoen model with only 3 parameters as opposed to the NWS model with 16 parameters could be used to estimate heat index. Based on this results, the heat index model obtained permits a more accurate prediction of the effects of environmental warmth in human, because it takes into account the rol