The almond trees blossomed ahead of schedule due to unusually warm weather during the past few weeks, and those blossoms are vulnerable to freezing temperatures.
"Upper 20s, we start getting damage," said Dale Van Groningen, an almond grower in Manteca. "Lower 20s can raise a lot of damage."
Van Groningen said the forecast has growers on high alert. Many are watering their orchards, not for irrigation, but to raise the temperature of the trees.
"The heat in the water and the moisture in the air helps protect the blossoms, causes ice to form around the blossom, which causes the blossom not to get any colder than 32," Van Groningen explained. "So that's a safe area right now at this time."
Some growers are also spraying chemicals to protect against blossom blight and brown rot, which can be brought on by the watering. But there's only so much that science can do.
"We're all keeping our fingers crossed and praying," said Van Groningen.
Complicating matters, not all growers have access to water at this time. Some rely on irrigation canals that are not flowing at this point in the season.