The software is a MATLAB function for prediction of refractivity in Nigeria. The function is developed by method of neural network training of refractivity data from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission. The required inputs are: Year, DOYc, DOYs, UTc, UTs, longitude, latitude, and altitude, in that order. where: DOYc=cos((2*pi*DOY)/365.25); DOYs=sin((2*pi*DOY)/365.25); UTc=cos((2*pi*UT)/24); and UTs=sin((2*pi*UT)/24); [DOY is day of the year, and UT is hour of the day in universal time] The output is refractivity in N-units.