David Bidstrup: Was December 2019 “hotter” than December 2018?

As the climate change hysteria continues to gather momentum, particularly in view of the recent bushfires, I thought I would do some rudimentary analysis to see whether the Adelaide summer of 2019/20 is “hotter” than 2018/19.

The data comes from the BoM, so it must be right!

The analysis is just a straight comparison of maximum temperatures for the corresponding days in each of the years. This post looks at December 2019 compared to 2018. The same will be done for January, ready in a few days, and February. Once February’s temperatures are in the entire summer, December, January and February will be compared.

The chart below shows the differences in maximum temperatures for each day in December 2019 when compared to the corresponding day in 2018.

Above the x axis shows when 2019 was “hotter” than 2018 and below shows when it was “cooler”. For 15 out of 31 days it was “hotter” and for 16 it was “cooler”.

December 1 was the equal third lowest maximum temperature in the 132 years of records I have for Adelaide. There were 6 days, 20% of the month, with a maximum temperature of 40 degrees or more. Looking at the 132 Decembers in the record there have been 70 days above 40, or an average of 5% of the days. 1897 had 4 and so did 1898. 1899, 1901 and 1941 each had 3 and all other Decembers, all 126 of them, had 2 or less.

It is possible to find the “hottest ever” day for each date in the 132 year record. The chart below shows the T Max for December 2019 compared to the “hottest ever” in the record.

January is looking very interesting. More after the end of the month.

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20 Responses to David Bidstrup: Was December 2019 “hotter” than December 2018?

  1. Every month, every year, is invariably hotter than the last. It only needs a blip in some ill placed gauge to prove that it was hotter. We replaced our old air conditioning units late last year and have only had them on maybe twice so far. A couple of times we’ve put to on heating cycle rather than start the fireplace.

    Yep, this climate change/global warming thing works in mysterious ways.

  2. Fair Shake of the Sauce Bottle

    I noticed how we moved closer to Summer the days generally appeared warmer. December in Victoria was definitely hotter than any month I had experienced since March.

  3. Chris

    I lit the wood fire a few times in December and twice in January so far to keep warm. I have not done that before in the twenty years I have lived in the Adelaide Hills.

  4. mem

    In the region I live in Victoria our temperatures have been below average for all but 20 days for the past six months and for the past two months rainfall has been above average.This month is double the average. But the BOM insists in its news reports that we have been hotter and drier than ever before. How can this be?

  5. Bruce of Newcastle

    Three days at +40 C here this summer so far, which is two thirds gone.
    I don’t think that is especially unusual.
    But then I’ve only been in the area 30 years.

  6. DP

    Dear Guest Author

    Facts seem to interfere with the global warming narrative, hence the faithful’s avoidance of facts, other than those which support, or can be tortured into supporting the narrative.

    May I respectfully point out a minor error in the label of the last graph? Ought it to read ‘2019’, not ‘2018’?


  7. Entropy

    You probably need to include mins and averages for completeness Mr Bidstrup.

  8. Professor Fred Lenin

    So you all agree that climate changes ? Mind you that hars only happened in the last 200,000 years ,pascoes aboriginal weather bureau records only go back that far,gaia knows what was going on then .

  9. Natural Instinct

    Probably best to integrate the numbers to form cumulative curves which smoothes blips. It also is a proxy for heat flux during month

  10. nb

    In my region of Victoria June 2018 to May 2019 was 0.2 degrees cooler on average for both maximum and minimum temps compared with June 2017 to May 2018. This year is probably cooler again (though October 2019 was 1 degree warmer than 2018). I’ll know in a few months. So far global warming seems to be producing a lot of cool.

  11. This is interesting:

    Rolls-Royce has announced that it plans to build, install, and operate up to 15 mini nuclear reactors in Britain, with the first set to go online in nine years. In a BBC Radio 4 interview with business journalist Katie Prescott on January 24, 2020’s Today program, Paul Stein, chief technology officer for Rolls-Royce, said that the company is leading a consortium to produce factory-built modular nuclear reactors that can be delivered for assembly by ordinary lorries.

    Currently, the world is undergoing a boom in nuclear power. According to the World Nuclear Association, there are 448 operating civilian reactors and another 53 under construction. However, almost all of these are being built in Eastern Europe and Asia, with China alone building more reactors than the entire Western world combined.

    Part of the reason for this is political with every reactor program in Europe or North America facing implacable environmentalist opposition and part of it is the expense of building and operating large reactors in an energy economy now dominated by cheap natural gas.

    Not in Australia that has plenty of uranium and places to store waste.

  12. deplorable

    I noticed how we moved closer to Summer the days generally appeared warmer. December in Victoria was definitely hotter than any month I had experienced since March.

    In southern Victoria it has been the coldest summer I can remember in my 70 years.
    The ocean temperatures are are at the lowest recorded or lower for this period.
    Night times and mornings are cold and Autumn appeared in the middle of December so I hope we are going to have a long Autumn up to Late June and not an early winter starting starting in March/April. There is no residual night time heat and when I asked an alarmist where all the heat from CO2 was I was told it is on the other side of the earth. Now that makes sense NOT.

  13. Warming due to increase of CO2 in the atmosphere should manifest itself mainly at high latitudes (poles), mainly in winter and mainly in the day time lows.
    That’s according to the “gold standard” of climate science, the IPCC assessment reports.
    This is because CO2 interacts with comparatively cold radiation bands.
    CO2 does NOTHING, nothing at all at the temperature levels we live in.

    Looking at maximum temperatures tells us nothing about mans emissions of CO2.
    Comparing temperatures from 1919 to temperatures in 2019 at a particular area, without comparing atmospheric pressure and wind direction is a waste of time.

    It’s all about atmospheric pressure and wind direction.
    If wind direction in 1919 was from the South or South East (ocean), and wind direction in 2019 was from the North or North West (desert), claiming the difference in temperature has any relationship to CO2 levels in the atmosphere is scientific nonsense.

    Yet we keep playing their games, like fricking idiots.

  14. ACTOldFart

    Don’y worry folks, come back in a few tears’ time and look at the BoM records again, and you will find that historical temperature data have in some mysterious way transmuted to fit the prevailing BoM ideology. Wasn’t that Winston Smith’s job in “1984”, to alter historical records to fit what Big Brother wanted? Apparently the BoM thinks it’s a manual, not a work of fiction.

  15. RobertS

    From bemused:
    “Rolls-Royce has announced that it plans to build, install, and operate up to 15 mini nuclear reactors in Britain…….”
    Britain also operates wood-fired power stations so as to cheat on its emission targets.
    So why couldn’t Australia get rid of fire fuel loads through mini wood-fired power stations located near national parks. Can anybody tell me why this is a bad idea?

  16. Can anybody tell me why this is a bad idea?

    First off, it would disturb the homes of grubs, ants and whatever other insects roam around in and under the ready to burn fuel.

    Secondly, burning wood is something that the Greens want to get rid of entirely, from home heating, BBQs to you name it, as it all causes CO2.

    As far as the Greens are concerned, if one of their policies deprives people of warmth, comfort or power, it must be a good.

  17. cuckoo

    My hairdresser told me today that, as far as she is concerned, Melbourne has had a cooler than average summer. Her simple measure for this is the number of times the weather is hot enough to swim comfortably in the sea around Phillip Island. Not many this year. Take that, BOM!

    For that matter, several gardeners told me how late summer was in Melbourne this year.

  18. A Dubbo

    A more critical figure for those on the land is evaporation rates : while how much monthly-yearly ‘income’ you have obviously matters, its when ‘expenditure’ goes through the roof, for a sustained length of time, that really hurts.

  19. Kneel

    “Warming due to increase of CO2 in the atmosphere should manifest itself mainly at high latitudes (poles), mainly in winter and mainly in the day time lows.” [and more – k]

    Radiation budget matters to “earths temperature” as seen from, say, Mars.
    What matters to us biologicals is the near surface temperature.
    We live in the troposphere – where turbulence rules.
    Convection and advection cooling is much more efficient than radiative cooling.
    (compare 1 bar radiator in a vacuum vs in atmosphere – temp in vacuum is higher)
    Latent heat of evaporation/condensation of water cooling is much more efficient than convection/advection.
    (evaporative coolers do actually work, tropical islands are cooler than tropical deserts etc)

    So what matter to us and other flora and fauna is much more likely to be from convection/advection than radiation, and much more likely to be from latent heat than convection/advection.

    But we will focus on radiation only – that is the diktat.

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