But more than half of U.S. cities with a population of at least 250,000 have sunnier, superior ratings to D.C.
Who are D.C.’s dark sky peers? Detroit and Chicago share D.C.’s dreariness score while New York and Philadelphia are slightly more dreary, and Minneapolis and Charlotte are slightly less dreary.
The nation’s least dreary cities all lie in the Southwest: Phoenix (1), Mesa, Ariz. (2), Las Vegas (3), Henderson, Nev. (4), and Bakersfield, Calif. (5). These are the places you can work on your golf game most days of the year, if you can stand the heat.
The mapped view of the index (below) clearly shows the dreariness void from the western Plains to the Southwest, where bright, sunny days rule. What may surprise some is that the Pacific Northwest and Northeast have a more or less equal share of sullen skies. Southeast Alaska is another place to avoid if you require a steady, natural dose of Vitamin-D.
This dreariness index was developed by Brian Brettschneider, a meteorologist based in Anchorage. He explains the methodology:
Three different variables are used in this analysis to come up with Dreary Index – total annual precipitation, number of days per year with measurable precipitation, and average annual cloud coverage. An inverse distance weighted surfacing technique was used to generate a gridded data set for the entire U.S. for each of the three variables.
The index hasn’t been published or peer reviewed. “[T]his methodology is completely arbitrary and far from perfect, but it is a start,” Brettschneider says.
I think it’s reasonably good first approximation as to what areas are most consistently sunny and dry versus cloudy and damp.