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Heat/cold degree days and Chill hours: Difference between revisions
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==Chill Hours and/or Air Frost==
A related measure, also reported by Cumulus counting the ''hours'' below a (different) configurable temperature threshold for the 12 month period starting on the 1st day of a configurable month, is '''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 45F or 7.5C for the period of 1st October to 30th April in the Northern Hemisphere. On Cumulus that threshold, and start date are the default, so you simply observe the reported value on 30 April. The current figure is viewable on the 'This Year' screen accessed from the View menu (only when the current year is selected), and is available via web tag <#chillhours> to be added to a web page template of your design.▼
▲The traditional way of calculating the accumulation of Chill Hours is the number of hours the temperature is below
The main 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 below 200 hours to around 1500 hours.
However, the way it can be configured on Cumulus will allow you to track air frost (defined as when temperature at the standard measuring height is below the freezing point for water) hours, ground frost (temperature close to ground level is below freezing) hours or any other measure being below the threshold parameter.
To see the number of Air Frost days, use the View menu to select 'This Month', 'This Year' or 'This Period' and choose the precise period of interest using the drop down selectors. (As at build 1058, there are no web tags to give air frost counts).▼
[[User:Sfws|Sfws]] 10:53, 1 December 2012 (UTC) (with thanks to Randy who raised Enhancement Request #117 and supplied some of the above text)
=== Air Frost ===
▲To see the number of '''Air Frost days''', use the View menu to select 'This Month', 'This Year' or 'This Period' and choose the precise period of interest using the drop down selectors. (As at build 1058, there are no web tags to give air frost day counts). The Chill hours web tag with a threshold of 0 degrees Celsius (32 Farenheit) will give '''air frost hours''' since the starting month.
==Cold Degree Days==
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