Clarissa Reyes, Orchard Advisor, Sutter-Yuba, Butte, and Placer Counties

Peach harvest can be predicted fairly accurately by the temperatures in the first 30 days following bloom. Other factors such as weather near harvest, soil, tree nutrition, and water status can also have some effect on harvest date. On average, we accumulate about 6,000 growing degree hours (GDH) during the first 30 days after bloom. Accumulation of much more than 6,000 GDH in the first 30 days after bloom leads to earlier harvest dates and smaller fruit size under normal thinning practices. 

The UC Davis Fruit & Nut Information Center hosts a peach harvest prediction model that calculates GDH based on CIMIS stations and predicts harvest dates of select cultivars.

This table provides full bloom dates for Sutter-Yuba Counties and growing degree hours 30 days after bloom (GDH30). It also includes the general harvest timing from 2004-2024 and the prediction for 2025.

Note: Sutter County Verona CIMIS weather station was used to calculate GDH30 for 2013-2025. Colusa CIMIS station was used to calculate 2012 and Nicolaus CIMIS station was used to calculate 2003-2011.