Check Monthly Means and Maximums
This website gives the monthly mean and maximum UV Indicies for the 58 forecast cities in the form of a map (just like the daily UV Index forecast map. A reporting city might have a range of readings from a maximum of 12 to a minimum of 3. The mean rating would be the average rating over a month.
Take a look at the maps for January. First read the monthly mean, and then look at the monthly maximum. What do you see? How do you explain the differences?
Now, mentally divide the United States into three horizontal sections going east-west across the country. Roughly, you'll have the northern third of the country (including Alaska), the center section, and the southern section (including Puerto Rico and Hawaii). Keep those divisions in mind.
Take a look at the data for the other months of the year. What do you see happening to the data for the mean UV Index reading and for the maximum reading? Can you make any general statements about the three sections of the country? Where and when would you be most likely to enjoy the outdoors without a high risk of UVB radiation exposure? How do you explain these findings?
If you would like to try a little data analysis on your own, follo