Los Altos Weather: Colder November

November in our town of Los Altos, California, was sharply colder, with the average high temperature plunging 15 degrees from October. The sudden cold triggered fall colors. The featured photo above is a western redbud, cercis occidentalis, a California native plant. The red seedpods in the background set off the yellow leaves. A haiku for autumn:

The morning sun shines
from dewdrops on tattered leaves --
fall fades to winter.

Los Altos Colder in November

In November our average high temperature dropped 15 degrees from October, to 63 degrees F. The overnight temperatures dropped 13 degrees. The Pacific Ocean off California is warmer than usual, fostering algae blooms and resulting neurotoxins that have delayed the opening of the dungeness crab season.

November high temperature drops 15 degrees from October
November high temperature drops 15 degrees from October

We received more than two inches of rain in November, slightly above average.

Almost two inches of rain in November
More than two inches of rain in November

Cumulative rainfall since January 2013 remains at 55% of normal, continuing the trend of the past year. Our drought is in its fourth year.

Rainfall since Jan. 2015 is 55% of normal
Rainfall since Jan. 2015 is 55% of normal

Water Conservation Continues

Urban users are still reducing our water usage to comply with the governor’s 25% water conservation mandate. In the five months since the order was issued, California urban water users have reduced consumption by 27%. Locally, our town conserved 35% in October and 37% since June.

As shown above, November is the beginning of our wet season with cooler temperatures. Going forward, we’ll use less water for landscaping, but it might be harder to continue conserving water. Californians use about half our water for landscaping, so the summer practice of cutting back on watering our lawns might not be enough to reduce water use by 25% during the winter.

Valley Aquifer Continues to Improve

Per the County Water Tracker report, the aquifer beneath our valley continues to improve steadily throughout 2015. In the bottom graph below, the groundwater elevation climbs steadily, even through the summer when we don’t have rain.

In every prior year since 2003, the groundwater elevation dropped during the summer. It’s not clear why this year is different. This summer, we pumped much less groundwater (middle graph) as urban users reduced water usage; although we pumped more groundwater than we put back through managed recharge (top graph). Another component, natural recharge, adds water to the aquifer, but it’s not reported monthly by the County.

Aquifer improves steadily throughout 2015
Silicon Valley’s aquifer improves steadily throughout 2015 (source: Water District)

Groundwater in California’s Central Valley

Groundwater in California’s Central Valley is in much worse shape, with groundwater levels dropping each year. California recently passed a bond measure to increase water storage, but we’re only at the assessing and planning stage. A farmer tried flooding his fields when surface water was available. He found that his crops improved slightly, and 75% of the water applied seeped into the sandy soil and became groundwater available for pumping. He and other farmer plan to expand this next year. This approach augments groundwater much sooner than building a dam.


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I enjoy travel, art, food, photography, nature, California native plants, history, and yoga. I am a retired software engineer. The gravatar is a Nuttall's woodpecker that visited our backyard.

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