This polygon shapefile represents the 22 year average monthly and annual measurements (kWh/m^2/day) of global horizontal irradiance (GHI) for the entire world. Lat/Lon values indicate the lower left corner of a 1x1 degree region. Negative values are south and west; positive values are north and east. Boundaries of the -90/-180 region are -90 to -89 (south) and -180 to -179 (west). The last region, 89/180, is bounded by 89 to 90 (north) and 179 to 180 (east). This polygon shapefile represents the average monthly and annual measurements (kWh/m^2/day) of solar direct normal radiation (DNI) for the entire globe. These data are regional averages; not point data. The source data was downloaded from the Surface Meteorology and Solar Energy (SSE) website as text files. The tabular data was then converted to the shapefile format.To provide investors and other stakeholders with reliable, verifiable and accessible information on the solar resource potential for the data domain. Global Horizontal Irradiance (GHI) products describe the solar resource available to a flat-plate collector oriented horizontal to the earth’s surface.