Blue Diamond Growers September report details harvest delays, weather impacts

California almond growers faced a month of contrasting weather conditions in September 2025, as harvest operations were impacted by monsoonal moisture, high temperatures, and regional variability across the San Joaquin Valley.

According to the latest Blue Diamond Growers crop progress report, daily high temperatures from September 3 to September 28 ranged from the low 80s to over 100°F, while morning lows remained more consistent, between the upper 50s and upper 60s. The early part of the month saw several days exceeding 100°F, putting additional stress on orchards and slowing irrigation schedules for some growers.

Monsoonal moisture brought heavy rain to several regions, temporarily halting harvesting for some producers. Eastern Fresno and Kings counties received more than an inch of rainfall on three separate occasions. A particularly strong thunderstorm on the night of September 24 affected Stanislaus and San Joaquin counties, scattering up to ¼ inch of rain and disrupting field operations for several days. Growers reported that wet conditions delayed shaking and drying processes, especially for early-maturing varieties.

Despite these challenges, many harvest operations continued at a rapid pace where conditions allowed. Growers moved from early-maturing varieties, including Nonpareil, Independence, and Fritz, to mid- and late-maturing varieties such as Carmel, Sonora, and Butte. Orchards less affected by rainfall proceeded with minimal disruption, while others had to prioritize drying nuts and adjusting harvest schedules.

Regional differences were evident throughout the valley. Northern areas of the San Joaquin Valley generally experienced lighter rainfall, allowing harvest to progress steadily. In contrast, central and southern regions faced repeated interruptions due to localized storms, prompting some growers to implement temporary storage solutions to protect harvested nuts from moisture.

Growers also reported ongoing attention to orchard floor conditions and equipment maintenance. Muddy conditions in some locations required extra care in moving harvest machinery and maintaining orchard roads. Irrigation schedules were adjusted to compensate for uneven rainfall, and monitoring of hull split progression remained critical to ensure timely harvesting.

Despite these challenges, overall crop quality remains consistent with expectations for the season. Growers continue to monitor pest pressures, hull rot risk, and nut moisture levels closely as harvesting progresses.

The next crop progress report is scheduled for Monday, October 27, 2025.

Photos courtesy of Christine Ivory, Ashley Correia, KC Clendenin, Austin Jackson and Mel Machado.