The odd observations aren’t valley wide but are more spotty and tend to be variety specific, he said.
Kevin Day, a University of California Cooperative Extension farm adviser in Tulare, said he’d seen similar oddities this season and attributed part of it to the lack of overall chilling.
Trees grew well into the fall last year, so at least 100 hours didn’t count toward the 900-hour chill threshold, he said. Trees also started to move in January, lopping off another 400 hours or so.
In addition, Day said some scientific evidence discounts the contribution of temperatures below 32 degrees Fahrenheit toward chill hours.
“So there are a lot of things that contribute,” he said. “And few people recognize and appreciate the absence of fog.”
During a clear, sunny day with an ambient air temperature in the 40s, bark temperatures may rise to 50 degrees or higher, Day said.
But winter tule fog, such as what the San Joaquin Valley typically experiences, helps insulate tree tissue against the sun, keeping the trees in a winter sleep. This year, the valley saw little, if any, fog.