Sunshine duration measures the duration of sunshine of a given location for a given time. It is expressed in hours per day or hours per year. Sunshine duration is an indicator of the cloudiness of a given location. The sunshine duration date can also be used to characterize the climate of a place. Although Europe has the cloudiest cities in the world, some of the US cities average less than 2,500 hours of sunshine annually. Here are some of the cloudiest cities in the US.
The Cloudiest Cities in the United States
Pittsburgh, Pennsylvania, tops the list of the cloudiest cities in the US. The city sees the sun for approximately 2,021 hours annually. Generally, it is cloudy in Pittsburgh for 77% of the year. In fact, it is the sixth-cloudiest city in North and Central America. November to January are the cloudiest months with the city recording at most 60 hours of sunshine.
The second cloudiest city in the US is Anchorage, Alaska. Anchorage experiences an average of 2,061.20 hours of sunshine annually. The city is often in darkness 76% of the year. December is often the darkest month in Anchorage with an average sunshine of 51.8 hours while the sunniest month is May with an average of 288.7 hours of sunshine.
Seattle and Columbus in Washington and Ohio respectively are the third and fourth cloudiest cities in the US. Seattle experiences sunshine for approximately 2,169.70 hours annually while Columbus experiences sunshine for only 2,182.60 hours. November, December, and January are the cloudiest months in both cities while both receive the highest amount of sunshine in July, averaging 312 and 260.9 hours respectively. Portland, Oregon completes the list of the top five cloudiest cities in the US with an annual sunshine duration of 2,340.90 hours. Portland experiences low sunshine period in December with an average of 67.8 hours of sunshine.
The city of Detroit in Michigan experiences an average of 2,436 hours of sunshine annually. The city experiences sunshine for only 27% of the year. The cloudiest months are November, December, and January with only 63.7 hours of sunshine in December. July is often a sunny month in Detroit with an average of 318 hours of sunshine. Indianapolis and Milwaukee experience sunshine for about 2440 and 2483.60 hours annually respectively. Like the above cities, the darkest months in Indianapolis and Milwaukee is December, with the cities receiving sunshine for approximately 102.4 and 102.8 hours respectively. Philadelphia and Chicago complete the list of ten cloudiest cities in the US. The two cities respectively experience sunshine for 2,498.40 and 2,508.40 hours annually.
Why Is it Cloudiest in December?
All the ten cities above experience least amount of sunshine in December. With an exception of Philadelphia, the rest of the cities experience less than 110 hours of sunshine. Anchorage and Seattle experience the least amount of sunshine in December at 51.8 and 52.9 hours respectively. About 16 cities in the US get more than 50 days of heavy clouds between November and February. December is often a winter month, characterized by cloudy skies, snowfall, and very low temperature. Although the winter season may last up to February, December is often notorious for cloudiness and low temperatures.