Is SLO County manipulating average rainfall totals?

January 29, 2017



Going by San Luis Obispo County’s average rainfall numbers, most of the county failed to reach average precipitation in the 2015/2016 rainy season. And with the county’s ever changing average rainfall numbers, much of the county is below averages even during the current season.

At the same time, county staffers are applying for grant monies based on drought conditions.

In San Luis Obispo County, average rainfall numbers have skyrocketed during the four years of drought. In some cases, the county’s averages do not equal the averages of the data provided.

For example, three years ago, the county listed the average rainfall in Santa Margarita at approximately 15 inches. Then last year, Santa Margarita received 16.57 inches of rain.

But because the county jumped the annual average rainfall amount to 20 inches, Santa Margarita fell short.

In November, the county bumped the average annual rainfall in Santa Margarita from 20 inches to 26 inches, which is unusual because since 2005 Santa Margarita has had over 26 inches of rain one time, during the 2010/2011 rain year. In another report, the county lists the average rainfall in Santa Margarita at 15.59 inches.

Flooding at Sycamore Mineral Springs Resort

Flooding at Sycamore Mineral Springs Resort in 2017

SLO County Public Works Director Wade Horton said that the county erred in the 26 inch average and would be correcting that number. As for the other differing accounts, Horton said staffers average different data sets which lead to varying results.

In December, the county listed the annual average rainfall at 14.7 inches in Templeton, just above the 13.86 inches Templeton received in the 2015/2016 rainy season.

During January’s heavy rains, the county bumped the average rainfall in Templeton from 14.7 inches to 19 inches while the data provided averages to 9.42 inches. With current rainfall totals during the 2016/2017 rainy season at 17.34 inches, Templeton has not yet reached average rainfall, according to the county’s latest average rainfall total.

For the city of San Luis Obispo, the national weather service reports the average precipitation is 19.02 inches. SLO received 19.02 inches of rain in the 2015/2016 season.

However, in another report the county claims the average annual rainfall in SLO at the reservoir is 25 inches. Then if you click on monthly reports, the county reports the annual average rainfall for the same site is at 15.59 inches.

When applying for federal grant monies, agencies are required to use official average precipitation numbers garnered through a preset methodology, according to The National Weather Service.

Currently, official averages utilize 30 years of data from 1981 through 2010. In 2020, the averages will be recalculated utilizing data from 1991 through 2020, said William Brown, a meteorologist with the National Archival Center for Weather and Climate.

Horton said the county’s official averages come from a 42 year period from 1955 through 1998.

“We feel our local data compiled through our network of gauges and local agencies would provide more accurate values,” Horton said. “See the links below that shows the National Weather Service average for Santa Margarita to have average rainfall values around 30 inches.”

However, the link was not to The National Weather Service or archives but to the Regional Climate Center which provides information from a group of regional, state and national agencies.


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If the steelhead make it up the Salinas River this year and spawn in the tributaries that will be rainfall at it’s best. Let’s hope some agency will take notice.

I notice, i am glad you do to. Its a very sacred thing to have our trout and steelhead here.

Is anybody at the county that smart, I know they are that dishonest.

If the rainfall averages are listed high , then our county elected officials who possibly have financial gains from large construction projects and or their donors will be able to win approval on such projects with ease . But in reality there still is a water shortage in slo county . An average wine grape plant needs 13 gallons of water a day , slo county has millions of wine grape plants , massive v-8 engines running 24 hrs a day pumping water running on natural gas at these vineyards .

Nailed it! A very sad sad industry, and a very sad truth. It draws in the psychopathic billionaires with no moral value on nature preservation, for nature and us humans. The wine industry, and our local politicians, will truly deplete ancient aquifers. It only takes a decade or two of industrial use.

Oh, a shout out to Justin vineyards and their lack of moral conduct! Yelp is a great way to share “facts” about these vineyards as well.

This is simply how the game is played: if we’re not lying, cheating, and stealing, we’re at a distinct disadvantage to acquiring grant money, because everyone else is lying, cheating, and stealing. Not to worry… the complainers become awfully silent when actual cash comes their way.

Kind of reminds me of when I here them predict the severity of the fire season. It’s either we didn’t get enough rain so everything is dry and it’s going to be a bad fire season or we got too much rain and everything is growing so there will be a lot of vegetation so it’s going to be a bad fire season. So I wonder is there ever just the right amount of rain so the fire season danger is average or low? But then an average or low fire season wouldn’t give them more money to prepare of the “bad” fire season.

Best case scenario is government ineptitude … Worst caste scenario is government dishonesty/corruption to acquire grant money.

My best guess is it’s a little of both

Government at its best. After getting caught manipulating data in their favor the typical answer is “oh we made a mistake.” Unfortunately mistakes seem to be the norm. Wouldn’t it be nice to hear them say that they got it right with no controversy.?

The big problem with government is for the most part efficiency would result in smaller budgets and a smaller workforce. Government hires these people and we are told that after extensive testing, interviews and background checks that the best have been chosen. But whenever a decision has to be made an outside consultant is hired to make the decision. Efficiency at it’s best and that way someone else can get blamed if a “mistake” is made.

How is a grant going to impact how much water we have? Seriously, all it does is provide more money for staff to make up “studies” that will say whatever another higher-up wants them to say. If we didn’t waste money like this, maybe we could pay down our stifling national debt, or use it on something that would actually make a difference, like building or maintaining a reservoir. But that might have a negative impact on the environment according to some other study somewhere funded by some other grant. And we still call ourselves a free country…

This sort of confused mess is so typical of much of the work done by our government. They just want the money to pump up their budgets. It’s not to help the citizens. It’s to pump up their salaries and benefits. They don’t work for us anymore. We work for them so we are supposed to just shut up and open up our wallets and pay our taxes. Our paychecks belong to them and if we are good boys and girls they will let us have some of the money to pay our bills and take care of our families.

Only the past 30 years? Don’t we have a century worth of rainfall averages from the same locations? Sounds like someone is cheating. Or they want to have more deceptive control of our water bills.

A lot of the data was gathered using non standard rain gauges and methodologies. The same problem exists when using historical data to try to determine the facts about global climate change.

Not so, Johnny. A lot of climate change data comes from measuring GHG content of ice that’s thousands of years old. Can’t apply non-standard methods argument to that one. Anyway, there aren’t weather records back far enough for global warming to be proved or disproved that way.