Last updated December 5, 2017

California Decreased Precipitation

There is considerable evidence that changing weather patterns due to climate change are at least partly responsible for recent declines in precipitation in California.

Statewide trends

Changing weather patterns due to climate change are at least partly responsible for the dramatic decline in precipitation during the two back-to-back winters in California—the winters of 2012-2013 and 2013-2014—that contributed to the severity of the California drought.

Researchers have linked climate change to the circulation patterns that produced the unprecedented high-pressure weather pattern known as the “ridiculously resilient ridge” that blocked storms from the state.[1][2]


Regional trends

A study looking at data from 1979 to 2014 finds up to a 25 percent decrease in precipitation in the US Southwest related to an increase in high pressure, anticyclonic conditions during this time in the North East Pacific.[3]

Globally, models show that many mid-latitude and subtropical dry regions will see a decrease in precipitation by 2100 should global emissions continue to increase.[4]