Chill Hours Up Substantially for 2020-21 Season

Feb 9, 2021

Chill Hours Up Substantially for 2020-21 Season

Feb 9, 2021

Had a good question today on whether or not this winter, measured in chill hours (that is to say, accumulation of hours of temperatures between 32 and 45 degrees F), has been colder than others.  Didn't seem that way, but it does serve to check.

If you haven't used this excellent tool from the UC Davis Fruit and Nut Research site, you should. The link here takes to you to the chill hour calculators, which run off the statewide CIMIS system of weather stations:

http://fruitsandnuts.ucdavis.edu/Weather_Services/Chill_Calculators/index.cfm

The station I am using is #129, which is just over the bridge in Pajaro.

The accumulated hours of chill start November 1, 2020 and run through February 8, 2021 are 671.  Compared to 448 hours last year through this date, it's a lot more.  Then we have 454 hours for the 2019-20 winter, 272 hours for 2018-19 winter, 421 hours for the 2017-2018 winter and 565 hours for the 2016-2017 winter.  

I include a copy of the chart comparing all of these chill accumulations below, note that years are labeled by the year the accumulation starts, ie 2019 marks Nov 1, 2019 through Feb 8,2020.

Great question, keep them coming!


By Mark Bolda
Author - County Director, Santa Cruz County and Farm Advisor, Strawberries & Caneberries

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