While a hard freeze failed to materialize Christmas night, central San Joaquin Valley citrus growers are under the gun Saturday night as freezing lows are expected to return.
Jim Andersen, meteorologist at the National Weather Service in Hanford, said overnight lows Saturday morning were slightly tempered by low clouds and, in some areas, fog.
Fresno dipped to 29 on Christmas night, while outlying areas like Lemoore chilled to 25.
Joel Nelsen, president of Exeter-based California Citrus Mutual, said those temperatures for short periods are ideal for most citrus varieties protected with water and wind machines.
The chance for the hard freeze returns Sunday morning, when temperatures are forecast to dip to as low as 23 in outlying areas, Andersen said. Fresno is expected to dip to 28 and Lemoore could see 25 again.
Fog could redevelop and keep temperatures from falling to lows that could affect the citrus crop.
Nelsen said that citrus growers would sleep during the day Saturday as they prepare to stay up through the night for the expected hard freeze, despite chances for another reprieve from citrus-damaging temperatures.
Nelsen said growers would start as early as 7 p.m. to fight the freeze by watering the citrus groves to add a layer of warmth. Mandarin orange and orange growers also fire up wind machines to keep warmer air circulating in the groves, where the fruit is susceptible to damage when extreme lows last for four hours or longer. Mandarin orange growers usually start the machines when temperatures dip below freezing, while orange growers can wait until the thermometer reaches 28.
Nelsen said that mandarin orange growers are 35 percent through their harvest with 50 million cartons of fruit picked, while orange growers are 30 percent through with 86 million cartons picked.