Temperature means, winter months, 2013-18

By popular demand*, here’s a full accounting of our winter temperatures since moving to the current location.

The stats really drive home just what an unusual winter this was, with the colder temperatures very much concentrated towards the latter part. I discussed the consequences of this for the deciduous fruit tree blooms in an earlier “planting“.

February’s mean low was more than four degrees below the five-year mean, and the March high and low were both 3-4 degrees below the five-year means.

December was also colder than normal, in terms of overnight lows although the daytime highs were the warmest experienced in a December thus far. The December cold was not as far below norm as we experienced our first winter here, 2013-14, when an extreme freeze was very costly to some of my citrus and other subtropical trees. Even the Eucs had damage that winter.

* Not really, I must admit.

Spring 2018. Or is it winter?

Sometimes in a climate like this one, the seasons kind of mash together. It was an unusually warm January, and some trees are in bloom now. Yet this morning the temperature was 30F and there were ice crystals on the grass.

First blossom one one of our almond trees–8 Feb.

The Flavor Delight aprium is in bloom, 11 Feb.

The blooming is not early, despite the January warmth. The almond depicted above usually has its first bloom around the same date in February: the 12th in 2017, 6th in 2016, 3rd in 2015. The Flavor Delight likewise tends to have its first several blossoms open around now: 14th in 2017,  7th in 2016, 15th in 2015.

What is somewhat more unusual is below-freezing temperatures at this time of year. (I am sure they were common at this point in February decades ago, but not recently.) The latest date of a below-freezing temperature in 2017 was 25 Dec. (29F, though it was 32 on 24 Feb.), in 2016 2 Jan., in 2015 3 Jan, and in 2014 5 Feb. And the current forecast calls for a few days of low temperatures in the 20s and 30s. This could be bad for pollination of the trees in bloom and for tender young leaf growth on the citrus and some other trees.

That is the nature of a Mediterranean climate–“spring” begins in early February, but winter can keep hanging on.

Fog and chill

It has been foggy in recent days. Far from my favorite kind of weather, especially when it sticks around all day.

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Sometimes, however, it can be good for the chilling hours accumulation that the deciduous fruit trees need. It is the tendency towards multi-day dense fog events that has made the San Joaquin Valley (south of here) historically a good place for prunes, peaches, apricots, and other fruits that need winter chill to set well in the subsequent growing season.

However, this has been the case with this fog event only on one day, when we had a low of 39F and, due to the fog, the temperature did not reach 50 till after 10:00 a.m. Prime chilling temperatures are roughly 38 to 45, with some continuing but significantly diminishing value up to the lower 50s. So that day was a good chill day.

Not so much since. For the past two days, the temperature has just hovered in the 45-51 range. That’s pretty close to useless.

(I had been meaning to write about the fog and chill even before I saw that a reader had commented at a post that is almost 12 years old, with a question about chill. One of the things I always appreciate on this blog is people commenting on old threads. I almost never close comments, no matter how old the thread, unlike some other blogs out there.)

Yes we have had some rain

After years of little more than an occasional storm, we had quite a series of storms, and they were big ones. The Sacramento River is mighty once again!

riverfront-homes

The view is from Old River Road, which is usually high above the water level. So are those houses. Now they are really riverfront properties in a perhaps overly literal way.

The river does not flood its banks, however, due to a remarkable piece of 1916 engineering called the Sacramento Weir and its manually operated gates. Last week was the first time this had been opened in over a decade.

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(short video; click to open in a new window and play)

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That is Old River Road running over the Weir, and parallel to it, the Sierra Northern Railway.

When the river reaches a certain level, the gates of the Weir are open and the overflow spills into the vast tract of low land known as the Yolo Bypass.

yolo-bypass

The levees around the river and the bypass protect not only houses, but farmland. For instance, this recently planted nut grove (walnuts, probably) that is directly across Levee Road from the bypass. grove-beyond-levee

Below is a photo of the Sacramento River looking upstream. Those trees are growing on the steep bank of the normally dry levee.

sac-river-upstream-view

The Sierra Northern crosses another section of the bypass that is fed by a weir farther upstream. Here it is on a trestle that is normally high above the wetlands. A road runs through there, but at ground level, which is, for now, now well below water level. (View from the I-5 causeway.)

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Interesting cloud feature today

It’s been a mostly cloudy day. But really, only here. Most of the Central Valley and northern California region has actually been clear. This narrow cloud band has been parked over our area almost all day.

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(Screen shot from NWS satellite image)

Here is what it looks like from ground level.

Narrow cloud band 10June2016

With the help of the satellite image, I can now be certain that the straight line direction down the middle of this cloud band is looking more or less right at Marin County. At the tiome that I took the photo (around noon), the band was crossing the shore just between Point Reyes and the Golden Gate. It has been slowly creeping southward, but very slowly. We are now (almost 3:00 p.m.) just under the band’s northern edge, and a re-check of the satellite imagery shows it is crossing the shore directly over the Golden Gate–and also even narrower.

Underneath it here, the temperature has been in the lower/mid 80s, a welcome relief from the 100+ temperatures we had earlier in the week. The fruit trees are certainly a lot less stressed today.

The first big storm

We have been at our current location for about twenty months. There has not exactly been a lot of rain during that time. Till yesterday. It rained from early in the morning till late at night, sometimes heavily, amounting to around three and a half inches. It brought our total to the month to 5.7, whereas from 1 July to 31 October we had had only 2.3. And the 6-10 day outlook says more is probably on the way!

So we finally see how well the property drains, or to what extent we get standing water. Early returns are favorable. It drains just fine, and there is no water standing in the one completely flat area where I put in some fruit trees.

Apple trees, among others; the branches on the ground were put there by me. I pruned them the day before to reduce the “sail” effect, given forecast very high winds (which were less than feared).

There is not even the slightest water standing at the bottom of the big hole where a former owner attempted to put in a pond. Now we see why he had no luck!

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View towards the north

There is just a little bit of standing water in our pasture, visible beyond the Eucalyptus near the center of the image. Just over the fence, however, the neighbor has quite a nice little lake. When I was out there earlier, I could hear geese honking nearby. And I’ve heard some frogs. They should be quite happy today.

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View towards the west/northwest

Snow

I don’t know when it last snowed at this elevation (1500 ft) in San Diego County, but it would have to have been many years.

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It’s pretty, but not really the best thing for citrus and avocado trees. Or stone-fruit trees that are already in bloom. (That’s the Mesch Mesch Amrah plumcot in between the mandarin and the avos.)

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Here it is as it was falling last night, around 9:30 p.m.:
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Many more photos at the Flickr site.