[[File:1960- Groundwater loss - depletion - Central Valley of California.svg |thumb |Within a long period of groundwater depletion, short periods of recovery were mostly driven by extreme weather events that typically caused flooding and had negative social, environmental and economic consequences.<ref name=NatureComms_20221219>{{cite journal |last1=Liu |first1=Pang-Wei |last2=Famiglietti |first2=James S. |last3=Purdy |first3=Adam J. |last4=Adams |first4=Kyra H. |last5=McEvoy |first5=Avery L. |last6=Reager |first6=John T. |last7=Bindlish |first7=Rajat |last8=Wiese |first8=David N. |last9=David |first9=Cédric H. |last10=Rodell |first10=Matthew |display-authors=4 |title=Groundwater depletion in California’sCalifornia's Central Valley accelerates during megadrought |journal=Nature Communications |date=19 December 2022 |volume=13 |issue=7825 |page=7825 |doi=10.1038/s41467-022-35582-x |urlpmid=https://www.nature.com/articles/s41467-022-35582-x36535940 |pmc=9763392 }} ([https://web.archive.org/web/20230130223801/https://www.nature.com/articles/s41467-022-35582-x/figures/4 Archive] of chart itself)</ref>]]The northern Central Valley has a hot [[Mediterranean climate]] ([[Köppen climate classification]] ''Csa''); the more southerly parts in [[rainshadow]] zones are dry enough to be Mediterranean steppe (''BShs'', as around [[Fresno]]) or even low-latitude desert (''BWh'', as in areas around [[Bakersfield]]). It is very hot and dry during the summer and cool and damp in winter when frequent ground fog known regionally as "[[tule fog]]" can obscure vision. Summer daytime temperatures frequently surpass {{convert|100|°F|abbr=on}}, and common [[heat wave]]s might bring temperatures exceeding {{convert|115|°F|abbr=on}}. Mid-autumn to mid-spring is the ''rainy season''—although during the late summer, southeasterly winds can bring tropical thunderstorms, mainly in the southern half of the [[San Joaquin Valley]] but occasionally to the [[Sacramento Valley]]. The northern half of the Central Valley receives greater precipitation than the [[semidesert]] southern half. Frost occurs at times in the fall months, but snow is extremely rare.<ref>{{cite web|access-date=July 26, 2009|archive-date=July 21, 2009|archive-url=https://web.archive.org/web/20090721042030/http://www.wrcc.dri.edu/narratives/CALIFORNIA.htm |publisher=.www.wrcc.dri.edu|title=Climate of California|url=http://www.wrcc.dri.edu/narratives/CALIFORNIA.htm|url-status=live|work=Western Regional Climate Center}}</ref>
