[UK monthly and weekly degree day figures](http://www.vesma.com/ddd/)
The calculation requires daily measurements of maximum and minimum outside air temperatures and a ‘base temperature’ Tbase, nominated by the user as an estimate of the outside air temperature at which no artificial heating (or cooling) is required.
(tags: [environment](http://del.icio.us/djdunc/environment) [degreedays](http://del.icio.us/djdunc/degreedays) [temperature](http://del.icio.us/djdunc/temperature) [energy](http://del.icio.us/djdunc/energy) [seewatt](http://del.icio.us/djdunc/seewatt))