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Are California’s Heatwaves Getting Worse?

August 20, 2020

By Paul Homewood



California is supposed to be experiencing a record heatwave, of which Death Valley is just one example.



Naturally the likes of the Guardian only want to tell you about temperatures in big cities or the airport at Stockton:



But what do stations relatively unaffected by UHI tell us?

Four years ago I analysed nine long term, high quality USHCN sites, none of which showed any upward trend in summer high temperatures. They pretty much cover all of California, so should give a good representation of the state as a whole. One incidentally was Lemon Cove, which I used as an example this week.

Below are CLIMOD charts for the others, showing the highest temperature recorded each summer. They range broadly from north to south, with Orland, for instance, north of Sacramento, and Redlands down towards Palm Springs. One station, Davis, has no data on CLIMOD.

Underneath each chart is the highest temperature recorded this week, though some stations have not been updated yet – If I remember, I’ll update next month!



Aug 2020 max – 108F





Aug 2020 max – 110F





Aug 2020 max – 112F



Aug 2020 max – 109F






In no case is this week’s peak temperature, where available, in any way unusual. Nor have  summer high temperatures been trending upwards.

I have just one more chart to show you, and I’ll use Lemon Cove again. This one plots the number of days above 100F each year:


We can see a gradual rise from the 1960s, but apart from 2017 and 2018, recent have not approached the high levels seen regularly in the 1930s and 40s.

This is a good indicator of the duration of heat waves, and along with the summer high temperature data shows that heatwaves in California are no more severe than they have been in the past.


The wording of the penultimate paragraph has been altered for clarification

  1. yonason permalink
    August 20, 2020 9:47 pm

    A Glimpse Of [Your]** Future

    Incompetent deceitful fascist idiots in charge, blaming you for nature’s vicissitudes, while screwing up your ability do deal with them.

    **Also in your future (as well as your present, apparently), media whose knowledge of grammar is a lot worse than mine. (Pardon the “racism,” but that bit (“…a glimpse of future”) at the end of the headline, tells me that the LATimes article Paul was commenting on might have been written by a non English speaking person. Could be foreign or native. Hard to tell given the degradation of our school system by the same idiots who are destroying our infrastructure.)

    Here’s a variation on glass half full/half empty as an analogy for “liberal” leadership…

    Is the peg too square, or the hole too round? Neither. The hammer just isn’t big enough.

  2. August 21, 2020 12:02 am

    Tip : BBC have sneaked in a 4 part advertorial series for “Greenblob Power”
    Thursday night in 4 different episodes over different northern BBC regions at 7:30pm
    Wind, Drax: Biomass, Gas, Nuclear
    eg Wind
    Powering BritainSeries 1
    Keeley Donovan heads 75 miles off the Yorkshire coast to see the building of the world’s biggest offshore windfarm. Hornsea One has broken every record for its size and scale – with 10,000 people involved in its construction in the North Sea. Keeley meets the staff who’ve made it
    happen – but can she get to the top of one of the 174 turbines in the field?

  3. George Reagan permalink
    August 21, 2020 4:55 am

    Give it time, gov Newsome will eventually torch ALL of Cali-for-nia. By then most of the states citizens will have moved elseware. The Great Migration actually started back in the 1970s . The east coast migration started in the 1980s.

  4. Phoenix44 permalink
    August 21, 2020 8:42 am

    Curious about the “August” record at Stockton – does that means it been hotter there in months other than August? In which case it’s a pretty pathetic extreme temperature.

    • C Lynch permalink
      August 21, 2020 9:56 am

      Of course that’s exactly what it means. It’s a bit like the “third warmest day in the second half of June in Lewes ever” type of “records” that we see being spewed out by the Guardian et al. on a regular basis.

  5. Bob permalink
    August 21, 2020 5:49 pm

    “We can see a gradual rise from the 1960s, but recent years still don’t hit the peaks seen in the 1930s and 40s.” The chart shows 2017 & 2018 (ie, recent years) do indeed hit the peaks seen in the 1930s and 40s.

    • August 21, 2020 6:41 pm

      I’m not talking the odd year.

      Clearly most years in the last couple of decades are the level seen in the 1930s and 40s

  6. A detail. permalink
    August 23, 2020 2:03 pm

    Fwiw, the ‘30s were a notoriously hot year in the USA, but not all the world. Dust Bowl, etc.
    But the articles’ main point that the attribution of the power cuts to climate change is BS easily stands. LA county reaching temps in the ‘90s is not at all unusual.

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