G'day John,

Summary
  • John raised excellent point
  • Twenty four hourly averages really should give you a good average.
  • In cold seasons a comparison between 24 hourly and max min will give you a drop not a rise
  • However, 24 hourly is not even used in towns very close to Ontario
  • More typical is seven temperature readings in a day with a daylight bias
  • Point of no "average" standard remains valid. The bottom line is you get different temperatures depending on which average you use.
  • Even for winter in a very cold location, with a daylight bias the average will still most often be much higher.


Main Points
The only time the average generally does not work is when there are 24 hour temperatures and the temperature is generally colder during the day. A winter or near winter day. This is one reason why US (and Canadian and Australian and New Zealand) data has not been effected that much. You get lower averages in the cold, higher in the hot and overall the result is - zero difference. Remember hourly temperatures done 24 hours a day require computerisation or 24 hour shift workers. That is not true for most temperature recording even today for most of the world. I did point out that the US data does match the satellites. This is also true for Canada (at least the lower portions - these are included in NASA's temperatures when they say "Continental US" - a bit rich but they simply do not have enough non urban effect temperatures without Canada and northen Mexico).

24 hourly temperatures is not how much of the world works. Where multiple temperatures are used the most useful ones are during the day and so that's what is being recorded.

24 Sept in Ontario a Special Case
Brrr. I couldn't stand it that cold. This was a strange day with 11 degrees at midnight and the coldest being about 10am. The temperatures do not follow a typical warming pattern because it had heavy cloud which kept the temperatures up overnight but the insulation did not last into the following day and it cooled down.

A More Typical Day Was 23rd - Calculations of its Averages
I'm not trying to find figures that agree with me, just more typical figures for your city, so I went back one day. Instead of 24 hours I took the typical two hourly temperatures used in many places starting at 6am and going through to 8pm plus the max and min: 11.7, 12.7, 13.4, 15.8, 15.9, 15.5, 15.6, 14.4, Min 10, Max 16. Average = 14.1. Min/Max Average: 13. But two hourly is also pretty rare so lets take a more typical 9am, midday, 3pm, 6pm, 9pm, Min, Max. Average is then: 14.1. The best average is hourly and for this day it is: 12.8. But typically averages add in min and max and you get: 12.83.

Variation of 1.3 Degrees depending on the Method Used
So we have 12.8 on an hourly basis, 13 if you use 2 hourly but not night temperatures, 14.1 if you use seven daily temperatures (currently a fairly typical way of creating the average). That is a larger variation that global warming for the century and Ontario is an Urban Effect city which pushes its total average up by about 1.5 to 2 degrees over the year.

Conclusion
My point remains valid. Not having a standard for averages and you get, well, you get garbage.


Richard
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PS. Sorry John, in my haste to have a look at the data (Sorry datum) you were using, I missed the little bit where you said you used July 3. Should have used that date.

Sane=fits in. Unreasonable=world needs to fit to him. All Progress requires unreasonableness