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Heat/cold degree days and Chill hours: Difference between revisions
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Heat/cold degree days and Chill hours (view source)
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A related measure is '''Chill Hours''', also reported by Cumulus counting the ''hours'' below a (different) configurable temperature threshold for the 12 month period starting at 00:00 hours on the 1st day of a configurable month. | A related measure is '''Chill Hours''', also reported by Cumulus counting the ''hours'' below a (different) configurable temperature threshold for the 12 month period starting at 00:00 hours on the 1st day of a configurable month. | ||
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, [ | 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, [https://cumulus.hosiene.co.uk/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 === | === Calculation of Chill Hours === | ||
The traditional way of calculating the accumulation of Chill Hours is the number of hours the temperature is below 45 degrees Fahrenheit or 7 degrees Celsius for the period of 1st October to 30th April in the Northern Hemisphere. One applicability is to stone and seed fruit as their exposure to low temperatures during the winter months will have a significant effect on the following harvest. Too few cold hours can result in poor quality and quantity of the crop. Fruit tree varieties prefer a Chill Hour rating from about 200 hours to around 1500 hours. | The traditional way of calculating the accumulation of Chill Hours is the number of hours the temperature is below 45 degrees Fahrenheit or 7 degrees Celsius for the period of 1st October to 30th April in the Northern Hemisphere. One applicability is to stone and seed fruit as their exposure to low temperatures during the winter months will have a significant effect on the following harvest. Too few cold hours can result in poor quality and quantity of the crop. Fruit tree varieties prefer a Chill Hour rating from about 200 hours to around 1500 hours. | ||
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[[User:Sfws|Sfws]] 10:53, 1 December 2012 (UTC) (with thanks to Randy who raised [ | [[User:Sfws|Sfws]] 10:53, 1 December 2012 (UTC) (with thanks to Randy who raised [https://cumulus.hosiene.co.uk/tracker.php?p=1&t=117| Enhancement Request #117] and supplied some of the above text) | ||
=== Air Frost === | === Air Frost === | ||
