Methods of calculating direct solar radiation received at normal incidence and the total solar and sky radiation received on a horizontal surface, applicable with accuracies within ±2.5 percent at Blue Hill Observatory, are presented. As many workers in radiation are content with accuracies within 10 or 15 percent, the same methods might be used with a lesser degree of accuracy in many other areas where atmospheric conditions approximate those at Blue Hill. With data of total solar and sky radiation received on a horizontal surface now available from more than 80 stations in continental United States, Canada, Alaska, and outlying islands, but with few values of normal incidence radiation in the same solar network, it is suggested that these methods can be used to estimate normal incidence for many new regions.