Crews will be fanning out across the San Joaquin Valley Monday afternoon, cutting fruit to assess the damage from the deep freeze over the last five days.
"Sunday night marked the coldest night," reports California Citrus Mutual, a non-profit that represents 60 percent of the state's citrus industry.
The group reports temperatures have fallen into the 20s and low 30s.
Right now 75 percent of the crop is still on the trees, and it's expected that some has been damaged.
However, the extent won't be clear for several days.
Growers say the maturity and sugar content of the fruit, at this point, should help minimize damage in the navel crop.
The same can't be said for mandarin and lemon crops.
According to California Citrus Mutual, those have a cold threshold of 32 degrees—and will likely see moderate damage.
It's estimated that growers have spent a combined $17.5 million on frost protection so far this season, which includes running fans and water to bring up the temperatures by a degree or two.
That's less than the $100 million spent at the same point last season.