Across the country, triple-digit temperature records were set in 150 places last year as the continental United States posted its warmest year on record, the government reported.
Sonoma County, bathed as usual in cool breezes off the Pacific Ocean, enjoyed mild weather, just right for growing a bumper crop of wine grapes.
"A perfect season," said Nick Frey, president of the Sonoma County Winegrape Commission.
Nearly 100 million people — about one-third of the nation's population — experienced 10 or more days of 100-degree or higher temperatures in 2012, the National Climatic Data Center said.
Santa Rosa's 170,000 residents sweltered at more than 100 degrees just twice — on Oct. 1 and 2.
At 100 degrees, people perspire and grapevines shut down, desiccating the fruit, Frey said.
Vines thrive at 87 degrees, he said, ideal for photosynthesis and for boosting the grapes' sugar level.
Growers had no complaints, bringing in a harvest of about 220,000 tons, or 10 percent above average. "It was nice," Frey said, adding: "It seldom is that way."
California joined the other 47 contiguous states in registering above-average temperatures last year, contributing to a 55.3-degree national average that was 1 degree warmer than the previous record in 1998 and 3.2 degrees above the average for the 20th century, the climate data center said.
Nineteen states had a record warm year and 26 more states has one of their 10 warmest. California's temperature tied for third highest on record.
Santa Rosa averaged 57.9 degrees, 1.3 degrees below average, according to Accuweather, The Press Democrat's weather forecaster.
Onshore winds held steady for the most of the year and "really kept you from baking," said Bob Smerbeck, Accuweather's senior meteorologist.
Only one month last year posted an above-average temperature in Santa Rosa, and that was May at a mere 0.7 degrees above average.
Last March was damp and cool, a full four degrees below average in Santa Rosa, while the Midwest was a whopping 15 to 19 degrees above normal, Smerbeck said.
Most of California breezed through a scorching year in which 99 cities from coast to coast had their warmest-ever average temperatures, including Fresno at 66.8 degrees, 2.4 degrees above its 30-year average.
The other five California cities on the climate data center's list were nowhere close to records, with sunny San Diego at 64.2 degrees and Los Angeles at 63.4 (both 19th warmest), Sacramento at 61.7 (18th warmest) and San Francisco at 57.6 (28th warmest).
Foggy Eureka averaged 51.7 degrees last year, its 59th warmest on record.
That Fresno heat is a gift to Sonoma County, pushing Central Valley air upward and drawing in the cool, moist Pacific air that nurtures pinot noir and chardonnay grapes along the Sonoma coast, West County and the Russian River, Frey said.
2012 also was a parched year for the U.S., 15th driest on record with an average 26.57 inches of precipitation, 2.57 inches below normal, and a drought that gripped 61 percent of the nation at one point, the climate data center reported.
Again, Santa Rosa bucked the trend, with 41.29 inches of rain, nearly nine inches, or 27 percent, above average.
And Smerbeck said it was "hard to tell" if the nation's record warmth last year was part of global climate change.