The storm that dampened the Bay Area over the weekend was like an old friend who doesn't visit much anymore.

And with good reason. Despite Saturday's healthy soaking, when it comes to 2013, it's been dry. Record dry.

Even including Saturday's showers, the Bay Area has received less rain this year from Jan. 1 to mid-September than during any year in recorded history, back to the Gold Rush.

Through Sunday, only 3.94 inches of rain had fallen since New Year's Day in San Francisco, which has the oldest rain gauge west of the Mississippi, dating back to 1850. San Jose and Oakland also are seeing record dry years for 2013 so far.

But as dire as that seems, meteorologists say it's not as bad as it looks.

"Don't panic yet," said Bob Benjamin, a forecaster with the National Weather Service in Monterey. "It has been dry, but we need to look at all the winter rain from the end of last year to put it in perspective."

Northern California has a Mediterranean climate, which means dry summers and mild, wet winters most years. Last November and December, it rained 50 percent more than normal across the Bay Area. Those early winter storms filled reservoirs and recharged underground aquifers.

So when the rains stopped in January, water districts had enough in storage so that no Bay Area community had mandatory rationing over the summer.


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"It's been a bone-dry year. We have noticed. But we're not concerned right now because our reservoirs are in good shape," said Abby Figueroa, a spokeswoman for the East Bay Municipal Utility District, which provides drinking water to 1.3 million people in Alameda County and Contra Costa County.

The district's reservoirs are 71 percent full.

It's a similar story in San Francisco and the Peninsula. Residents there receive Hetch Hetchy water, and that reservoir in Yosemite National Park is 77 percent full.

In Silicon Valley, the 10 reservoirs operated by the Santa Clara Valley Water District are 43 percent full, but that's in part because five of them can't be filled to the top until seismic upgrades are done. The district has two years' supply for its 1.8 million customers stored in underground aquifers.

Still, say water experts, the upcoming rainy season is important. If the super-dry spell continues, mandatory water restrictions are likely next summer.

"If we still haven't had much rain by March or April, then we'll definitely be talking about it," Figueroa said.

Early signals aren't great: Water temperatures in the Pacific Ocean are normal now, not warmer than normal, which would indicate an El Niño year on the way. And El Niño years often mean wet winters in Northern California. The chance of an El Niño developing through Dec. 31 is only 6 percent, according to climate scientists at the National Oceanic and Atmospheric Administration. In other words, "La Nada."

"We're not seeing much of a trend at all," said Michelle L'Heureux, a meteorologist with NOAA's Climate Prediction Center in College Park, Md.

When it comes to Bay Area rainfall so far in 2013, records are falling.

During 1998 -- the wettest year in the 163-year history of record-keeping -- more than 9 times as much rain fell from Jan. 1 to Sept. 21, a staggering 35.74 inches, as fell this year so far. This year's paltry total is only 29 percent of the historic average for that period, 13.79 inches.

The dry 2013 has meant tough times for Central Valley farmers who rely on water from the Delta. Pumping there has been reduced by federal and state agencies this year because of the arid spring.

But in Santa Clara County, most farmers are OK, said Jennifer Scheer, executive director of the Santa Clara County Farm Bureau in Morgan Hill. That's because they pump water from underground and don't rely much on the Delta. Yet ranchers are feeling the pinch, she said.

"It didn't rain enough to grow as much grass this year as they would like," she said. "So ranchers had to sell off cows earlier or spend more money buying hay."

Most water districts and meteorologists measure each rain season from July 1 to June 30 -- rather than by calendar year -- to include all the winter rains in the yearly total. When the past year is looked at over that time period, San Francisco received 16.61 inches of rain. That ranks 43rd among driest years back to 1850, and is nowhere near as bad as the driest year, 1975-76, when just 7.19 inches fell.

Some weather experts don't even like to talk about rainfall from Jan. 1 onward.

"It's nonsense. It's like redefining a baseball game from what happened after the fifth inning," said Jan Null, a meteorologist with Golden Gate Weather Services in Saratoga.

Like other forecasters, Null said he has no idea whether this winter will bring needed storms.

"I've never seen any skill in long-range weather forecasting, anything out past a month," he said, laughing. "If somebody could do that accurately, they'd be richer than Bill Gates and Warren Buffett combined."

Paul Rogers covers environmental issues and resources. Contact him at 408-920-5045. Follow him at Twitter.com/PaulRogersSJMN.