In central California, farmers are working hard this weekend to protect citrus and other crops from freezing.
They've had sprinklers going at night to coat fruit with ice, to act as insulation against lows in the 20s.
Farmers with vegetables like broccoli and cabbage have covered their fields with plastic.
Many homeowners made a run on local hardware stores for insulation to keep water pipes from freezing; some are sold out of foam pipe wraps.
Freeze risk for citrus, other crops in California