Heat/cold degree days and Chill hours: Difference between revisions

This measure is sometimes called ''Growing Degree Days'', because it relates to plants or insects rather than heating systems, but that seems a strange labelling because growth in most plants and insects responds to warmth, although some seeds need a period of chilling to stimulate germination and as described below some fruit needs chilling to promote development. However, [http://sandaysoft.com/forum/tracker.php?p=1&t=262| enhancement request #262] reports a different definition of ''Growing Degree Days'' based on summing daily: ((MaxTemp - MinTemp)/2 - BaseTemp) for all days where the value is positive (negative values are not subtracted).

=== Calculation of Chill Hours ===

 

On Cumulus that threshold, and start date are the default, so you simply observe the reported value at the relevant time on 30 April/1 May. To use a different threshold add ''ChillHourThreshold=x.x'' to [[Cumulus.ini#Section:_Station| station section in Cumulus.ini]] where x.x is the temperature you want in your normal Cumulus temperature units. Use ''ChillHourSeasonStart=mm'' in [[Cumulus.ini#Section:_Station| station section in Cumulus.ini]] where mm represents month number (1=January, 12=December) to change the season start. The current figure is viewable on the 'This Year' screen accessed from the View menu (only when the current year is selected), stored in [[today.ini]], and is available via web tag <#chillhours> to be seasonal or longer period added to a web page template of your design. Should you miss checking the reported value on 1 May, then for a few days, you can look in the backup sub-folder for the necessary archived today.ini. In the current version of Cumulus, a new archive of the data sub-folder is taken just after each rollover, but note that Chill hours are counted in Cumulus by calendar day (therefore some interpolation is needed if your rollover is 9am/10am).