Winter chill
Winter chill, the extended period of cold temperatures critical for fruit and nut trees, is decreasing at certain sites in California’s Central Valley.
Changes in Climate
Overview: Changes in Climate
The evidence that the climate system is warming is unequivocal. In California, consistent with global observations, each of the last three decades has been successively warmer than any preceding decade.
Precipitation
The yearly amount of precipitation over California has become more variable since 1980. With warmer temperatures, more precipitation has fallen as rain than snow in recent years.
Extreme heat events
Since 1950, extremely hot days and nights have increased. Nighttime heat waves have markedly increased since the mid-1970s.
Drought
California has become increasingly dry over the past century. The most recent drought from 2012 to 2016 was the most extreme since instrumental records began.
Cooling-degree days
Average temperatures have increased in California over the past century. As a result, the energy needed to cool buildings during warm weather — measured by “cooling degree days” — has increased.
Annual air temperature
Air temperatures have increased over the past century, with nighttime temperatures increasing to a greater extent.
