There’s no way of predicting if Mother Nature will continue to shower the Bay Area when we turn the calendar to 2015, but this month is shaping up to be one of the wettest Decembers in decades — at least in some parts of the region.

On Monday, San Jose received 0.59 inches of rain, making it the city’s rainiest December in almost 60 years. And even more rain is forecast through Friday.

So far this month, San Jose has received 6.62 inches of rain, the most in December since 1955, when 9.26 inches of rain was recorded. It’s also the fifth-wettest December in San Jose since rainfall records began in 1874, according to Jan Null of Golden Gate Weather Services.

San Francisco has received 8.43 inches this month, the most since December 1950.

San Jose and San Francisco are the only two Bay Area cities with rainfall records going back long enough for a good historical comparison, Null said. Oakland is next, but he said there have been problems with the totals for the city, and the recording station moved from the airport to the museum.

As of Monday, Oakland’s total of 8.74 inches in December wasn’t close to surpassing its previous December record, set back in 2002 with 11.87 inches recorded, according to a forecaster and the weather service online records. Oakland’s rain total records date back to the 1940s, according to the weather service.

This month’s totals are expected to increase even more in coming days as a series of smaller storms comes through. But meteorologists say this week’s totals won’t come close to the single-day soaking the Bay Area received Thursday. And the latest forecasts suggest Christmas week is likely to be dry.

San Jose’s December record is 10.55 inches, which was set in 1889. In San Francisco, the record for wettest December is 15.16 inches, set in 1866.

Despite the impressive December totals, weather experts are cautiously optimistic about rainfall for the remainder of the season, which runs through the end of June.

Both Null and Diana Henderson, a forecaster with the National Weather Service, point to 2012 as an example when an above-average December rainfall was followed by bleak totals in the subsequent months.

In December 2012, San Jose received 4.24 inches, and San Francisco had 7.11 inches, numbers Null described as “really decent.”

“And then the rain stopped,” Null said.

Over the following six months to the end of the rain year, San Francisco received just 3.51 inches and San Jose registered 2.24 inches, with much of the Bay Area finishing the season with well-below average rainfall totals.

But it’s hard not to hope this extremely wet December is a precursor of things to come that may lead California out of its debilitating drought.

“It’s really hard to base an entire year off of one month,” Henderson said. “If you look at some previous years, you’ll see our heaviest months are still to come. Hopefully it will pan out and remain that way.

“Some years, we get our lion’s share early, and it drops off. I would hesitate to say it will be like this the rest of the winter. I’ll be cautiously optimistic about it,” she added.

San Jose normally receives 42.9 inches of rain in an average three-year period. Between June 2011 and June 2014, it received just 22.8 inches, leaving the city 20 inches short.

Similarly, San Francisco is 19 inches behind, Oakland 24 inches.

By one Department of Water Resources estimate, California will need six more major storm systems like Thursdays this season to fill the reservoirs and end the drought.

“Every journey of 100 miles starts with one step,” Null said. “To have a good strong December certainly gives us a big leg up on what we need for the entire year.”

Contact Mark Gomez at 408-920-5869. Follow him at Twitter.com/markmgomez.