Weather whiplash: A month after freezing temps, Santa Rosa breaks 96-year-old heat record

An early spring heat wave drove area temperatures toward the 90-degree mark Tuesday, eclipsing Santa Rosa’s nearly century-old record high by three degrees.

The mercury reached 89 degrees in downtown Santa Rosa, obliterating the record of 86 degrees set March 22, 1926.

Neighboring inland cities in Sonoma and Mendocino counties also contended with temperatures in the high 80s, but Santa Rosa stood out. The 89-degree reading was the hottest for the date since record keeping began 120 years ago and was 23 degrees above the 30-year average for the date.

Just a month ago, overnight temperatures reached below freezing for several successive days, prompting freeze warnings around the area. Special efforts were made to get the unhoused in shelter, and grape growers employed frost protection strategies for vines at risk of losing buds.

Now, in a demonstration of the increasingly common phrase “weather whiplash,” the heat is on, thanks to a strong ridge of high pressure across the region and warm, dry offshore winds raising temperatures up to 20 degrees above normal, the National Weather Service said.

The mercury hit 88 degrees at the Charles M. Schulz-Sonoma County Airport.

However, long-term records are maintained from a separate site in downtown Santa Rosa going back to June 2, 1902, where the temperature typically differs by a few degrees from the airport north of the city, National Weather Service Meteorologist Roger Gass said.

While the record high downtown for the date had been 86 degrees, the record low was 29 degrees in both 1912 and 1917, Gass said.

The thirty-year normal, a metric that is re-evaluated every decade, is 66 degrees for downtown Santa Rosa, Gass said.

The summerlike weather, combined with spring break vacation for many school districts around the region, sent lots of folks to coastal parks, including Doran Beach Regional Park, which announced a full parking lot by noon.

“There were a lot of young families out there,” said Regional Parks Manager David Robinson, who took the day off to be with his own boys, part of it at the beach.

He said the Russian River parks were not as busy, in part because the water is low due to the drought. Summer dams put in later in the year are likely to raise the water level somewhat.

Grape growers, meanwhile, are expecting to see significant growth in the vineyards with the warm weather — a welcome occurrence, as long as there isn’t any frost on the horizon.

A span of warm weather in late January prompted some early bud break, waking up the vines just in time for the February freeze, said Balletto Vineyards founder and owner John Balletto. The level of potential crop loss isn’t yet known, even as another strong push of growth is on due to even higher temperatures now.

It’s all good, he said, unless there’s a freeze or even “a cold rain from up by Alaska.”

Weather forecaster Rick Canepa said there may be some rain coming late Sunday or Monday from up north, bringing potential for as much as a half to an inch of rain in the North Bay hills.

But he said it would more likely come with overnight lows in the 40s than below freezing, or so it appeared Tuesday.

In the meantime, another warm day was in store for Wednesday, though not quite as hot as a day earlier, with a shift to onshore winds bringing cooler temperatures and a few more clouds, Gass said.

Gass said that teasing out how much of this week’s temperature spike could be attributed directly to a changing climate instead of the normal variations in weather was tough.

But he noted that “having the driest January and February combined on record, around the Bay Area, and some of the hottest days, that’s another really large swing that’s starting to stick out more and more.”

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.