This report covers the conditions and activities observed from September 3 through September 28, 2025. The next report is scheduled for Monday, October 27, 2025. In the event of any significant occurrences prior to that date, this site will be updated as soon as possible.
California’s almond growers endured widely ranging weather conditions during the final weeks of summer, with locally heavy rain interrupting the harvest for many San Joaquin Valley growers. Daily maximum temperatures reached their highest level early in the period, with readings reported at just over 100 degrees. Temperatures then oscillated between the low 80’s and 100 degrees, varying under the influence of monsoonal moisture flows moving northward over the state. Morning low temperatures exhibited greater stability, ranging between the upper 50’s and upper 60’s throughout the period.
As with the month of August, the greatest variable on September’s weather came in the form of monsoonal moisture that brought locally heavy rain to the orchards on three separate occasions. “Regular” monsoonal flows, and thunderstorms generated by a dying hurricane delivered over an inch of rain in areas of eastern Fresno and Kings County, grinding harvest operations to a halt in areas receiving the greatest rainfall. Up to the final week of the period, most of the San Joaquin Valley’s almond growers had not had any weather-generated difficulties. However, a particularly nasty thunderstorm that passed over Stanislaus and San Joaquin counties during the night of September 24 scattered as much as ¼ inch of rain across the landscape, interrupting many growers’ field operations for several days. And while growers in the Sacramento Valley did receive unwanted rainfall, due to the southern origin of the storms, San Joaquin received much more.
Harvest operations progressed at a feverish pace during September as growers moved from early harvesting Nonpareil and Independence to mid and late maturing varieties. The 2025 harvest can be described as one of extremes. For those who escaped impacts from the previously mentioned monsoonal flows, the harvest has progressed with few difficulties. However, those receiving the greatest amount of rainfall have experienced significant interruptions as they work to promote drying of wet product in the orchards. The timing of the storm events was such that one grower mused, “It’s Tuesday, so it must be raining.”
Observers are reporting that early maturing varieties, including Nonpareil and Independence, Price and Sonora have all been removed from the orchards. Harvested product is either being delivered to huller/shellers for immediate processing or sent to stockpiles to be processed after harvest operations in the orchards have been completed. Growers moved quickly into the Carmel, Butte and Padre and had begun shaking advanced plantings of late maturing Monterey and Fritz late in the period.
Following initial reports of elevated reject levels in the first Nonpareil and Independence deliveries of the season, damage levels dipped below those experienced in the 2024 crop. However, some have noted an uptick in damage in pollinator varieties, most likely the impact of the third flight, or generation, of navel orangeworm. Using information identifying the exact cause of the rejects in their deliveries, growers will immediately meet with their Pest Control Advisors to evaluate their pest management strategies with the intention of further reducing losses in the next crop.
As noted in our last report, some growers have been dealing with infestations of web-spinning spider mites. Growers with the most intense infestations have seen their orchards defoliated. Some have noted that the trees are pushing new leaves, which can inhibit the following year’s crop.
Huller/sheller managers have noted that the crop contains thick, heavy hulls that have been slow to dry. This has reduced flow rates through the hulling and shelling process and resulted in low turnout percentages, with the weight of almond kernels as a percentage of the in-hull weight delivered from the orchards. The elevated moisture level in the hulls also creates concern for fires later in the season due to spontaneous combustion of the stored hulls.
Those who have completed their harvest for the year quickly moved on to post-harvest tasks, working to prepare the orchards for the 2026 crop. After irrigation is done to restore moisture deep in the root zone, generally, the next order of business is to “float” the orchard floor to remove the buildup of soil that forms beneath the window. Application of soil amendments and post-harvest fertilizers, either liquid materials included in the irrigation water or solid materials such as potassium formulations, are also being completed.
Growers will spend the next few weeks working to complete their harvest as expeditiously as possible. Irrigations will continue until local districts end their delivery season for the year.
By Mel Machado
Photo Credits: Christine Ivory, Ashley Correia, KC Clendenin, Austin Jackson and Mel Machado
