Snowfall has decreased 15% in California since the late 1970s, with precipitation falling as rain instead.
On current emissions trajectories, the state will likely experience 60% to 90% decline in the annual average number of days below freezing by 2100, as precipitation increasingly shifts from snow to rain and snow melts earlier.
The Sierra region will likely experience significant increases in extremely hot days, with a five to 10-fold jump iby late century. The region’s current 30-year average for days over 95°F is roughly eight days per year, but this will likely increase to 13 to 19 days per year on average over the next 25 years, 21 to 33 days by mid-century, and 37 to 84 days–or nearly three full months–of extremely hot days by the end of this century. The tail risks are more significant: there is a 1-in-20 chance of more than 22 days per year of extremely hot days in the near term, 41 days by mid-century, and 103 days over 95°F each year by century’s end.
Source: Bloomberg et al. (April 2015) From Boom to Bust? Climate Risk in the Golden State. The Risky Business Project.