Longitude

What it is

The longitude of the site in decimal degrees. Positive values are east of Greenwich and negative values west of it. The longitude and the time zone together convert the clock time of the weather data into the position of the sun.

Typical values and how to get it

Pick the location on the map, or read it from the weather file header. A wrong sign, or a time zone that does not match the weather file, shifts the sun by hours; check the two together.

API

site.longitude