What Your Rain Gauge Says About You

The measuring tube from an official CoCoRAHS (Community Collaborative Rain, Hail and Snow Network) rain gauge. There’s nothing in it.

To answer the question implicit in the title: I really have no idea.

But your rain gauge, be it an expensive electronic home weather station variety for which you’ve shelled out many hundreds of dollars or a humble plastic tube that you read manually, will tell you one thing for sure this winter in California: It’s been much drier than normal throughout our rainy season, and it’s dry now.

So far, our backyard gauge has caught 6.83 inches of rain since last July 1 (which is the “rainfall year” that used to be the standard for the National Weather Service in California; a few years ago, the agency switched to the “water year,” which runs from Oct. 1 through Sept. 30. For what it’s worth, I recorded exactly one one-hundredth of an inch (.01 inch) from last July 1 through Sept. 30; the Berkeley normal for that three months totals .31 inch).

Where was I? Right — 6.83 inches of rain since last July 1. The Berkeley “normal” for July 1 through March 8, as calculated for the “official” Berkeley station on the University of California campus, is 21.49 inches. One way to look at that: We’re about 15 inches short of our “normal” wet season rainfall. Another way: We’ve gotten just 31.8 percent of that “normal” precipitation.

I’d love to be able to compare my numbers with that station on campus, which has been keeping records since 1893. But I can’t right now. The Department of Geography employee in charge of the weather station and sending data to the public National Centers for Environmental Information database retired sometime in the last few months, and the most recent available numbers from that station are from last September. I’m told that the later data will be forthcoming … soon.

(Much later: The grad student in charge of collecting the UC Berkeley did get back to me after this was posted. The rainfall at the campus station totaled 7.99 inches at the time this post was published.)

Since the UC Berkeley info isn’t available, I’ve checked to see what other nearby CoCoRAHS (Community Cooperative Rain, Hail and Snow Network) rain watchers have recorded and compared those to the official Downtown San Francisco record for the season.

One gauge, 1.4 miles to the northwest in Albany, has recorded 6.99 inches since July 1 (.16 inch more than my gauge); another, 1.6 miles to the southwest in South Berkeley, has measured 6.39 inches (.44 less than mine). And San Francisco’s Downtown station, which has the longest continuous rainfall record on the West Coast — going back to the summer of 1849 — has picked up all of 7.41 inches since last July 1, or 39 percent of normal.

A look at the California-Nevada River Forecast Center makes it clear that our local percentages of normal — figures in the 30 to 40 percent range — are pretty typical across our slice of Northern California:

Percentage of “normal” seasonal rainfall recorded from Oct. 1, 2020, through March 8, 2021, by way of the California-Nevada River Forecast Center.

One other observation for now, by way of Jan Null, a former National Weather Service forecast who works as a consulting meteorologist. As he noted last week, California is in its second very dry winter in a row and we have a recent historical parallel, from 2013, that we can use to measure advancing drought effects across the state:

Berkeley in January: A Foot (or More) of Rain

I can hear the rain pounding down right now, just as it has been for much of the last few days and for most of January.

Our modest electronic rain gauge shows we’ve had 4 inches of rain in the last five days and 9.5 inches since Jan. 7; that’s 9.5 inches in half a month. I am a lousy record keeper, but I know we’d had about an inch and a half or 2 inches this month before Jan. 7. So we are looking at 11 to 12 inches of rain so far this month. Which I call a lot.

The current month’s record’s from Berkeley’s “official” weather station on the Cal campus aren’t available (the most recent available through the National Climate Data Center are from November; I’ve failed over the years to figure out how to get more current numbers from the folks who monitor the station).

But to double-check my half-informed guesstimate, I asked my friend Pat, whose boyfriend Paul is a weather geek with his own home weather station, how much rain they’ve seen at their place up in the Berkeley Hills. The caveat is that their place is at an elevation of 900 feet or so and is likely to get more rain than we do here at 120 feet above sea level in the Berkeley flats.

Nonetheless, here’s Pat’s Sunday afternoon report: 13.05 inches total rainfall since Jan. 1 and 4.59 inches over the past five days.

And one other cross-check, this time from a spot that I know is significantly wetter: Tilden Park’s Vollmer Peak, at 1,905 feet the highest point in the Berkeley Hills. The state Department of Water Resources reports readings from a gauge on the peak. It shows 16.5 inches for the month so far and 4.9 over the past five days.

I’ll declare it confirmed: What people have been seeing all over Northern California and the Bay Area is true in Berkeley, as well — we’ve had a very wet January. Although … not the rainiest we’ve ever seen in these parts.

Berkeley’s official weather record goes back to 1893. According to the precipitation data maintained by the Western Regional Climate Center, Berkeley’s rainiest January occurred in 1916, when 16.54 inches were recorded at the campus station.

Because the record for that month is incomplete — five days are missing — the January 1916 record is not officially considered our rainiest January. Instead, almost-as-soggy January 1911, when 15.99 inches fell, is listed as our January maximum. Huh — one could question the logic in that.

Either of those months — January 1911 or January 1916 — would qualify as Berkeley’s rainiest month on record.

Assuming I’m correct and we’re in the 11- to 12-inch mark for January rain, this would mark Berkeley’s 14th January with 10 inches of more or rain. And it would be the rainiest since 1973, when 12.47 inches fell.

Today’s Drought Note: How Dry Is It in Sacramento?

It’s so dry that …

Well, by way of the California-Nevada River Forecast Center, go-to source of data on winter storms during winters when we have those, here’s the latest attention-getting drought note:


Checking the site for the Sacramento office of the National Weather Service, I find a slightly different take on the history:


There may be a change on the horizon: Forecasters say models are showing a change in the weather pattern at the beginning of February, and we may see rain then. This late in the season, anything short of the deluge the state saw in the winter of 1861-62, when San Francisco got 24.36 inches of rain in January alone, will fall short of being a drought buster. Longer-term analyses say that the odds are good the next three months will be drier than normal here. But at this point, any kind of rain would be refreshing to see.

Dry December Update

“Rain, rain, rain, rain,
Why’d you cause me so much pain?”
—”The Rains Came,” Sir Douglas Quintet

Southern California got a little spritz of rain over the weekend—nearly a fifth of an inch yesterday in the desert town of Blythe. Here, it’s dry, and the California-Nevada River Forecast Center sees only a small chance that rain will fall over the northern part of the state in the next week (and that will be far north of the Bay Area). Our local National Weather Service forecast office, in Monterey, reads the models the same way: “Dry and mild weather will continue through at least the next 7 days … with little variation in the upper level weather pattern. A series of storm systems will move towards the region over the next week … but pass to the north and east of the area. ” The longer-range outlook from NOAA’s Climate Prediction Center is for drier and warmer than median weather.

Here’s the local NWS table on precipitation so far this year. And below that, today’s theme song

Station July 1-Dec. 18, 2011 % of Normal July 1-Dec. 18, 2010 % of Normal July 1-Dec. 18 Normal July 1-June 30 Normal
SFO Int’l Airport 2.87 50 5.76 101 5.69 20.11
Oakland Airport 3.06 52 6.66 113 5.91 17.42
Mountain View Airport 1.73 45 3.24 85 3.83 13.35
San Jose Airport 1.53 39 3.05 77 3.95 15.08
Santa Rosa Airport 4.45 42 13.19 123 10.70 31.91
Salinas Airport 3.31 103 3.45 107 3.21 12.91
San Francisco Downtown 3.35 47 7.88 111 7.08 22.28

California Water: Is the Drought Over?

Is California’s drought over? OK, let me take a step back. Yes, I realize one could debate whether the last three years in California actually constitute a drought. But that’s a discussion for another time. For now, I think everyone can agree that we’ve had lower-than-average precipitation for the past three years.

The only reason to ask the question is that, after the first half of the wet season delivered only spotty rain, we’ve had a pretty solid week of downpours. Water is sluicing into our reservoirs, and the hills are greening up. All of that is a sign of what we think winter should be here. ( My favorite water statistic of the week: when the storms were at their heaviest around Lake Shasta, California’s biggest reservoir, water was flowing into the lake at about 500,000 gallons per second. That’s 1.5 acre feet, or about enough for three “average” households for a year, every second.*)

Amazing numbers like that aside, the people who get paid to think about whether the drought is over say “not yet.” The San Jose Mercury News published a good summary of the situation a couple days ago: “It’s soaking. But the drought’s not over just yet.”

That story does contain one bit of typically odd California thinking about rain and water, though. It quotes a very knowledgeable local meteorologist, Jan Null, about where we stand in terms of normal rainfall. He says: “”We need February and March to be wetter than January to really end the drought. You have to look at the long game here. This is a great start, but we need to keep it going.”

The last sentence stopped me: “This is a great start, but we need to keep it going.”

Of course, Mr. Null recognizes better than most that the amount of rain we get and when we get it is out of anyone’s control. Still, “we’ve got to keep it going.” Maybe he’s a professional rainmaker.

Once you understand the importance of water in California, once you get how crucial the winter rains are, there’s a score-keeping aspect to weather-watching here. It becomes second nature to study the rain gauge and the seasonal precipitation table as an index of performance, a reflection on whether a great collective goal is being attained. Lots of rain means we’re doing well (and that we can put the complexities of water supply out of our minds). A dry spell means we’re failing (and that there will be hell to pay, or at least the strong possibility of stringent conservation measures).

But in reality, there’s no performance going on. The rain is the rain, and the climate is the climate. California’s rainfall is famously variable. Dry spells can be counted on, and the current run of dry years is the third we’ve had since I arrived in Berkeley in the ’70s. My first California winter, 1976-’77, was bone dry and was in fact the second year of the driest two-year period ever recorded here. A decade later, from roughly 1986 through 1992, we had another run of dry years. And if our winter rains were to stop now, we’d be in the fourth year of drier-than-normal years. In between these periods we’ve had average years and very wet years and years that didn’t quite hit the average. That might not be too different from anywhere else. The reason it’s a bigger deal here than it might be in, say, central Wisconsin, is that we have a six-month dry season, we need to store water to get through that, and we have 37 million people and millions and millions acres of farmland that need water whether it’s falling from the sky or not. Thus the need to believe we can wish the rain to keep going during the wet season and the tendency to feel disappointment when the winter turns into a string of dry, sunny days.

*500,000 gallons per second. Here’s the arithmetic: California Department of Water Resources figures (here: http://bit.ly/6HzIuu) show that in the hour between noon and 1 p.m. on Tuesday, January 19, the net inflow into the lake was 66,288 cubic feet per second. That’s the highest inflow figure for any single hour all week. One cubic foot equals 7.48 gallons. 66,288*7.48=495,834.24 gallons. One acre foot=325,851 gallons. And 495,834.24/325,851=1.52 acre feet. Per second. For the entire 24 hours of the 19th, Lake Shasta’s inflow averaged just over 1 acre foot a second.

Bonus feature! KQED’s latest California Reservoir Watch map, updated earlier today:

View KQED: California Reservoir Watch in a larger map

Rain Chronicles

This will not be a banner precipitation season for California–though always keep your eye out for the neighbor building boats and inviting in pairs of every creature. But that doesn’t mean it is without interest. For starters, it could well be a significantly below-par year for rain and snow here, which would make it three such years in a row, and that’s never good news. Already this year, the probability of a third drought year is getting spun by the governor and his water people to bolster their campaign for more dams and fancy plumbing. You have to admire their pluck; with the state $40 billion in the hole just to buy things like bullets for the Highway Patrol, stun guns for prison guards, paper clips for the bureaucrats, and adult diapers for the Legislature, the guv and company are talking about getting the taxpayers to spring for another $10 billion or so.

Anyway. Talking rain at work today, someone produced a list that purports to show that a place called Blue Canyon, on Interstate 80 (and the Union Pacific) in the Sierra, is one of the 10 wettest locations in the Lower 48 states (and the wettest in California). It gets 68 inches of precipitation a year. No way, no how that is the wettest place in California. My money’s on Honeydew, a hamlet on the Mattole River in Humboldt County. With our neighbors, the Martinuccis, we actually drove through Honeydew once on our way up the coast. I have an impression of a general store and a narrow bridge. There’s some evidence–disappointingly scanty, to be honest, but it includes an official-looking listing of each state’s wettest location–that Honeydew regularly gets 100 inches plus of rain a year.

And leaving Honeydew out of the picture for a moment, there are at least half a dozen places up on the North Coast–towns like Fort Dick and Crescent City in Del Norte County–and further south–like Cazadero in Sonoma County–all average more than 70 inches a year.

Not that Blue Canyon doesn’t deserve attention. Some with the Weather Service credit it with being the snowiest recording station in the Lower 48 (averaging 240.8 inches a year). But here’s my favorite: in a table succinctly labeled “Mean Monthly and Annual Number of Hours with Measurable Precipitation, with Percent of Hours and Maximum 1-Hour Totals,” Blue Canyon is way out ahead of any California listing: On average, it’s precipitating there 10.6 percent of the hours in the year–928 hours and 30 minutes, roughly. Of course, that would make it just a run-of-the-mill place in much of Oregon and Washington (Portland’s percentage of precipitation hours per year: 10.9).

Water, Water Everywhere

We’re in a drought here, or what they call a drought in California, so I’ve been thinking about water. Unfortunately, I’ve been thinking in terms that use lots of words and have led so far to dead ends. (Just a minute: a blog, dead ends–what’s the problem?) Anyway, for now, just a couple of numbers, from Shasta Lake, the biggest of the big network of reservoirs built to turn California’s mountains and rivers into a reliable water bank. In the past month at Shasta Dam, on the Sacramento River just north of the city of Redding:

–More than 20 inches of rain has fallen.

–The amount of water in the reservoir has increased by about one-third, from 1.41 million acre feet to 1.86 million acre feet.

–The amount of the increase over just a month, 450,000 acre feet, is about enough water to supply 2.2 million people for a year.

–But that’s not a lot in term of the demand for water here: About 80 to 85 percent of the “developed” water in California–water that’s impounded behind dams and delivered on demand to customers around the state–goes to farms. The rest goes to industry and residential users. The population of California is 36.5 million.

I’ve got lots more numbers kicking around, but that’s enough for now. In the next installment–soon!–I’ll try to make some sense of them.

The Things I Think About

Here’s a pointless exercise I spend time on nearly every morning. The Chronicle has a weather page. Not up to the standard of the Chicago Tribune’s page, which is the best I’ve seen; its overseer, Tom Skilling of WGN, has apparently worked with people at the paper to give the page real dimension and depth; they actually make an effort to tell readers something meaningful about the science of weather, they pore over the record books to put the current weather in some sort of meaningful context, and they highlight interesting weather happenings outside the Chicago metro area.

But back to the Chronicle’s weather page. It’s full of numbers, and it features a giant Bay Area map. But it’s really narrow and dull when you get down to it. One feature it has presented presented since I started reading the paper regularly, back in 1976, is a list of a dozen California cities and their current seasonal rainfall. From Crescent City in the north to San Diego in the south, the list reports precipitation in the last 24 hours, how much rain has fallen since the start of the current season (which runs from July 1 through June 30), how much fell in the same period last year, the “normal” seasonal rainfall to date (an average taken over the last 30 years), and the “normal” total for the entire season. Doesn’t that all sound interesting?

I have a daily habit of checking the precipitation numbers if it’s been raining. I have a minor, ongoing fixation about one particular fact: how Oakland’s rainfall stacks up against San Francisco’s. As a resident of the East Bay, it’s a source of pride that humble Oakland has been, on average, a little more rainy than its vainglorious cousin across the Bay Bridge — Oakland’s season normal is 22.94 inches versus San Francisco’s 22.28. But a worrying trend has developed: In several recent years, San Francisco has wound up ahead in the rain race; this year, Oakland is nearly two full inches behind, 25.22 to 27.21.

It makes you wonder whether the fix is in — maybe West Bay meteorologists are doctoring the results to claim Bay Area Rain Capital honors. It makes you wonder what the penalty is for tampering with an Official Government Rain-Measuring Instrument.