Fruit & Nut Research and Information Center
Fruit & Nut Research and Information Center
Fruit & Nut Research and Information Center
University of California
Fruit & Nut Research and Information Center

Pistachio Bloom Cast

Pistachio Bloom Cast | Model Development

(model in beta testing)

Projected bloom dates are modeled using chill and heat accumulation collected from hourly temperatures downloaded nightly for more than 100 CIMIS weather stations. Select your nearest CIMIS station for progress towards bloom this year and estimated bloom date for the last five years.

The timing of bloom is a result of both the accumulation of winter chill and spring heat. This model assumes pistachios need to accumulate 900 Chill Units (calculation details), followed by 11,500 Growing Degree Hours.

Chill accumulation count begins November 1st. Each year column shows chill accumulation up until the threshold of 900 Chill Units. It then shows the Growing Degree Hours accumulation up to the threshold of 11,500 GDH. The first day at or above 11,500 GDH is the estimated date of bloom.

CIMIS Station

This model is still in testing. Estimated bloom dates are just that – estimates. It may be helpful to compare estimated bloom dates of previous years with bloom at your site to see how well the model does at your location.

Page Last Updated: February 27, 2012
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