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

Heat/cold degree days and Chill hours (view source)

269 bytes added , 20:20, 24 June 2013

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→‎Air Frost: grass frost added for completeness

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 [[User:Sfws|Sfws]] 10:53, 1 December 2012 (UTC) (with thanks to Randy who raised [http://sandaysoft.com/forum/tracker.php?p=1&t=117| Enhancement Request #117] and supplied some of the above text)
 === Air Frost ===
-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.
+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. Sometimes the term 'grass frost' is used for whan the air temperature goes below 4 degrees Celsius, it roughly corresponds to when grass looks white due to frozen dew (water is more dense below 4 degress than above 4 degrees so the cold moisture falls onto the grass).
 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).