Where do you find the amount of days of sun per year you might expect in a certain area? For example, Phil., PA?

Wataya | Posted in Green Building Techniques on April 6, 2009 11:24am

Is this information available on the net?

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Martin Holladay | Apr 06, 2009 12:29pm | #1
Al,
Insolation maps are available on many Web sites. Here are three:
http://howto.altestore.com/Solar-Insolation-Map-USA/a44/
http://www.wholesalesolar.com/Information-SolarFolder/SunHoursUSMap.html
http://americansolareconomy.com/bloggerimages/Modified_Us_pv_annual_may20.gif
Riversong | Apr 06, 2009 02:42pm | #2
For what purpose? The number of sun days per year is an almost meaningless number. What's more important for most applications is the intensity of solar radiation, the monthly solar availability, and the monthly sun angles.

There are many links for a variety of solar data at:
http://www.builditsolar.com/References/SunChartRS.htm
user-282515 | Apr 06, 2009 09:54pm | #3
Al,

You can also visit http://www7.ncdc.noaa.gov/IPS/ for complete climatological data for your area.