A major limitation in predicting the ultraviolet-B (UVB) and ultraviolet-A (UVA) irradiance on humans, plants and aquatic organisms is the difficulty in determining the areal distribution of UV radiation for dose estimation. This study analyzes the difference in spectral irradiance at 300nm (representing UVB) and 368nm (representing UVA) between 12 paired locations in the USA over two summer growing seasons (May through August of 2000 and 2001). Daily dose estimates were made for irradiance at 300 nm and 368 nm from multi-filter rotating shadow band radiometer measurements made during May through August of 2000 and 2001 at 15 locations of the United States Department of Agriculture UVB Climate Monitoring Network. The spatial correlation of global 300nm irradiance was similar to that of 368 nm to a distance of 400 km. Beyond 400 km, 300nm global daily dose was more highly correlated between stations than the 368 nm global daily dose. Correlations with increasing distance between measurement locations in the direct beam UVB were generally greater than those for diffuse UVB while correlations for both direct beam and diffuse UVA daily dose were similar. The aerosol optical depth was not correlated to the 368 nm daily dose. The ozone column thickness was not correlated with the 300 nm daily dose. Results indicate spatial correlations in global 300 nm and 368 nm daily dose of approximately 0.8 can be expected for distances of 100 to 200 km.