EXTREMES
131 complete years, measured — and these are their endpoints.
What an extreme is on this site
A DIVISIONAL AVERAGE, NOT A THERMOMETEREvery number on this page is an area average over a climate division or the whole state — the same NOAA nClimDiv series behind every other page here. That makes these extremes quieter and stranger than the ones in a record book: the hottest month ever measured statewide is an 81.5°F average that folds the Sierra crest in with Death Valley, and no thermometer anywhere ever read it.
One gauge, one afternoon — the 134°F world record, the −45°F morning at Boca, the 451-inch snowpack at Tamarack — is a different object, certified by different people. Our companion site keeps that register: the record book on Golden State Weather, every entry named to its instrument. This page is what the averaged record has done; that one is what single instruments have done.
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The years
WARMEST TEN AND COOLEST TEN, STATEWIDE MEAN TEMPERATURETwo lists from the same 131 years. Read the dates, not just the values: every year on the warm list is 2014 or later, and nothing on the cool list is newer than 1971 — no year in the last half-century has come close to re-entering it.
The water years
WETTEST TEN AND DRIEST TEN, OCTOBER–SEPTEMBERPrecipitation extremes, unlike temperature's, are scattered across the whole record — which is the no-trend result on the precipitation page shown a different way. The driest water year in 131 is not 1977 and not 2021: it is 1924, and it holds the mark in five of the seven divisions too.
The months
SINGLE-MONTH ENDPOINTS OF 1,500-ODD MEASURED MONTHSOne month is where an average can still be shocked. The hottest and coldest single months statewide, and the wettest — with the current partial year excluded from every annual statistic on this site but eligible here, because a month is complete the moment NOAA publishes it.
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The division ledger
EACH DIVISION'S OWN ENDPOINTSThe same four endpoints for each of the seven divisions. Read down the warmest-year column first; it is the shortest argument on this site.
A divisional extreme mutes every local one inside it. For station records — certified single-gauge extremes with dates and instrument IDs — use the record book; for the official arbiter of new state records, the State Climate Extremes Committee.