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Heat/cold degree days and Chill hours: Difference between revisions
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===General Explanation===
It allows you to specify, in the units you have selected to use in your implementation of Cumulus, the two thresholds (they do not have to be the same, although they are in the picture that shows the thresholds traditionally used in the UK in the pre-computer age of standard reference look-up tables). Since it introduced electronic processing in the 1960s, the UK Meteorological office has used 22 Celsius for Cold degree days,
'''If you later change the threshold, you will have inconsistencies on your reports:'''
* The report will quote the new threshold, but only ''after the time'' you changed the threshold, will Cumulus calculate the degree day counts based on the new threshold for the minute by minute interrogations of the weather station.
* For the period from ''when you installed'' Cumulus version 1.9.2 (this also applies for any earlier days added by 'create missing' with the new version) until day before changing threshold, the integrated figures as stored in [[dayfile.txt]] at the end of the meteorological day are quoted in the report. These counts were integrated on a minute-by-minute basis using the thresholds that existed at the time that the figures were stored in the daily summary log. It is therefore not possible to affect these degree days
* For days that were logged before you installed version 1.9.2 (or a later build if you missed out that version), there are no degree day figures in dayfile.txt. The values for the NOAA report are calculated simply by comparing the average daily temperature with the current threshold settings, so in this case any change in the threshold does apply retrospectively for those days although the calculation is inconsistent with later days.
Cumulus 1.9.2 was available as default version from 5th October 2011, or as beta Build 1004 from 21 July 2011.
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