The current drought in California is the worst the state has seen in at least 1,200 years, according to a recent study published by the American Geophysical Union.

Scientists at Woods Hole Oceanographic Institute and the University of Minnesota reconstructed California’s temperature and precipitation history back to 800 A.D. using tree ring data.

Hidden in this millennium of data they found as many as 66 dry periods of at least three to nine years. In the entire 1,200 year period they studied, there were only three droughts that were similar in nature to the current drought.

Though none have been as severe as what California has seen in the three years since 2012. Not even the historic droughts of the late 1970s, nor the late 1980s.

The study also found that 2014 was the worst single drought year in the past 1,200 years, and that approximately 44 percent of California’s 3-year droughts have gone on to last another year, or longer.

California’s current lack of rainfall is not unprecedented in the 1,200-year record. The study concludes that the current drought was a result of both below-average precipitation and record-breaking high temperatures, and that the latter could have intensified the drought by about 36 percent.

This week has been particularly rainy one for California, which is being blasted by a series of storms that are channelling moisture into the state. San Francisco has seen over 3.5 inches of rain since Monday, compared to 2013, when they only received 0.35 inches in the whole month.

Crazy weather in California Show all 21 1 /21 Crazy weather in California Crazy weather in California Freak California weather (Top) Full water levels are visible in the Bidwell Marina at Lake Oroville in Oroville, California. (Bottom) Low water levels are visible in the Bidwell Marina at Lake Oroville on 19 August 2014 in Oroville, California Paul Hames/California Department of Water Resources via Getty Images/Justin Sullivan/Getty Crazy weather in California Freak California weather (Top) The Green Bridge passes over full water levels at a section of Lake Oroville near the Bidwell Marina in Oroville, California, in 2011. (Bottom) The Green Bridge passes over low water levels at a section of Lake Oroville near the Bidwell Marina on 19 August, 2014 in Oroville, California Paul Hames/California Department of Water Resources via Getty Images/Justin Sullivan/Getty Crazy weather in California Freak California weather (Top) Full water levels are visible in the Bidwell Marina at Lake Oroville on on July 20, 2011 in Oroville, California. (Photo by Paul Hames/California Department of Water Resources via Getty Images) OROVILLE, CA - AUGUST 19: (Bottom) Low water levels are visible in the Bidwell Marina at Lake Oroville on August 19, 2014 in Oroville, California Paul Hames/California Department of Water Resources via Getty Images/Justin Sullivan/Getty Crazy weather in California Freak California weather The Sun begins to peek out from below a layer of smoke blowing north from fires in southern Oregon and Northern California as it sets on the Willamette Valley near Eugene, Ore AP Photo/The Register-Guard Crazy weather in California Freak California weather Members of the CAL Fire Vina Helitack crew battle a spot fire as the fast-moving wildfire called "Sand Fire" burns near Plymouth, California REUTERS/Max Whittaker Crazy weather in California Freak California weather Highway 120 in and out of Yosemite National Park is closed due to firefighting efforts on the El Portal Fire burning in the Stanislaus National Forest and Yosemite National Park in California EPA/Stuart Palley Crazy weather in California Freak California weather An air tanker drops retardant on the fast-moving wildfire called "Sand Fire" near Plymouth, California REUTERS/Max Whittaker Crazy weather in California Freak California weather An aircraft drops fire retardant on a vineyard as firefighters battle the fast-moving wildfire called "Sand Fire," near Plymouth, California REUTERS/Max Whittaker Crazy weather in California Freak California weather Trees in Yosemite National Park are backlit by a sun turned orange by smoke from the El Portal Fire burning in the Stanislaus National Forest and Yosemite National Park in California, USA EPA/Stuart Palley Crazy weather in California Freak California weather Marin County firefighter Brett Grayson walks through a vineyard looking for spot fires from the fast-moving wildfire called "Sand Fire," near Plymouth, California. The fire, which started Friday, has burned 5 homes, 1300 acres, and is 20 percent contained, local media reported REUTERS/Max Whittaker Crazy weather in California Freak California weather One man died and 14 people were injured after a freak storm hit beachgoers Crazy weather in California Freak California weather A burn mark is seen on the walls of a home that was hit by a lightning strike on Haynes Lane in a residential area of Redondo Beach, California REUTERS/Jonathan Alcorn Crazy weather in California Freak California weather Shasta Dam, the largest Dam in California and the second largest in the United States as shown with Shasta Lake and Mt. Shasta in the background in Shasta Lake City, California EPA Crazy weather in California Freak California weather A woman shops for grapes at Monterey Park's Friday evening Farmers Market in Monterey Park, California. With the first six month of 2014 the hottest ever in California, the devastation of crops from California's drought is pushing household grocery bills higher as fewer acres of land are being used for planting and crop yields shrink as available water dwindles AFP PHOTO/Frederic J Crazy weather in California Freak California weather A motorboat cruises along the McCloud River Arm of Shasta Lake in Lakehead, California, USA. Water levels are 41 meters (135 ft) from crest and 36 per cent of capacity as California goes through its third straight year of dry weather EPA Crazy weather in California Freak California weather A tire along the Sacramento River Arm of Shasta Lake in Lakehead, California. California Governor Edmund G. Brown Jr., has declared a drought state of emergency and asking consumers to conserve 20 per cent of water. Mandatory conservations is now in effect in some counties EPA/JOHN G Crazy weather in California Freak California weather In search of his stray shot a golfer walks onto the cracked lake surface of the drought affected Laguna Blanca at La Cumbre Country Club in Goleta, California EPA Crazy weather in California Freak California weather At the start of August thunderstorms caused floods and mudslides in the south of the state at San Bernardino County, killing one person and leaving thousands stranded San Bernardino County Fire Department Crazy weather in California Freak California weather "Valley Of The Falls Drive and Mill Creek crossing is typically a two-lane road, now covered by runoff" the San Bernardino County Fire Department tweeted, showing the damage caused by the storms and floods San Bernardino County Fire Department Crazy weather in California Freak California weather Stranded campers receive meals and shelter at a community center staffed by San Bernardino County Fire Department volunteers and others San Bernardino County Fire Department Crazy weather in California Freak California weather An official of the Forest Home Christian Conference Center in Forest Falls, California, inspects damage on the property following thunderstorms on Sunday AP Photo/The Press-Enterprise, David Bauman

Their average rainfall for the entire month of December is 4.03, so the city is well on it’s way to at least making par. Los Angeles has racked up over 1.5 inches of rain so far this month, where the December average is 2.05.

However, much, much more rainfall is needed to put a dent in the drought.

Fifty five percent of California remains in an “exceptional drought” as of Thursday — the most severe classification on the scale used by the U.S. Drought Monitor, and 100 percent of the state remains in at least a moderate drought. Many of the state’s critical reservoirs remain well below their historical average.

While this week’s rain and snow will be a step in the right direction, California still has a long way to go to reach total drought abatement.

As of October, the National Climatic Data Centre was estimating that most of California’s central valley as well as Northern California would need anywhere from 18 to 21 inches of precipitation over the next six months to end the drought.

This week’s rains will be beneficial, but they won’t be nearly enough.