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Latest Cumulus MX release 3.6.6 (build 3082) - 1 June 2020 (please see important announcement regarding releases since 3.5.0)
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Apparent temperature difference cumulus 1 and MX

From build 3044 the development baton passed to Mark Crossley. Mark has been responsible for all the Builds since. He has made the code available on GitHub. It is Mark's hope that others will join in this development, but at the very least he welcomes your ideas for future developments (see Cumulus MX Development suggestions).

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BrunswickWeather
Posts: 20
Joined: Fri 11 Mar 2011 2:04 am
Weather Station: Fine Offset with Solar Sensors
Operating System: windows 10
Location: Brunswick Australia

Apparent temperature difference cumulus 1 and MX

Post by BrunswickWeather »

The apparent temps for today in Cumulus 1 is high 13.5 at 2:01 pm yesterday and low 8.0 at 6:21am. The days ends at 9am.
Cumulus MX 16.0 at 1::41pm yesterday and 9.1 at 6:51 am
Both are from same weather station but only one cumulus run at the time.
Which one is correct?
I presume different methods of calculation
Both Dayfile and May month files are available if required

BrunswickWeather
Posts: 20
Joined: Fri 11 Mar 2011 2:04 am
Weather Station: Fine Offset with Solar Sensors
Operating System: windows 10
Location: Brunswick Australia

Re: Apparent temperature difference cumulus 1 and MX

Post by BrunswickWeather »

This the Apparent Temp not the actual temp

BrunswickWeather
Posts: 20
Joined: Fri 11 Mar 2011 2:04 am
Weather Station: Fine Offset with Solar Sensors
Operating System: windows 10
Location: Brunswick Australia

Re: Apparent temperature difference cumulus 1 and MX

Post by BrunswickWeather »

Sorry read the wrong MX data
MX is 14.0 at 2:07pm and 8.2 at 6:22am
Much the same

sfws
Posts: 818
Joined: Fri 27 Jul 2012 11:29 am
Weather Station: Modified Fine Offset
Operating System: Win. 10 PC
Location: The Marches, UK

Re: Apparent temperature difference cumulus 1 and MX

Post by sfws »

I'm glad you realised you did not have a problem, both flavours do use same calculation. If you understand the PHP language, you can see the calculations in a function within the download in viewtopic.php?f=18&t=18096 post.

Where you will see a difference when you are switching between flavours is in what goes into daily summary. I had a period when I was just trying out MX, a while ago, and was running each in turn, so I actually saw this.
Derived values like Average Temperature, Wind Run, Total hours of sunshine, Heating/Cooling degree days, plus all the time-stamps. All of these are sensitive to which readings are included in the calculation of that derived value, and of course extremes reported are dependent on whether Cumulus is able to see them. When a particular flavour is not running it depends on catch up from the station logger, and those readings are less frequent so fewer can feed through into calculations, and you may miss extremes. At the same time the flavour that is running is sampling readings very rapidly (depends on station type how frequently) and for those times these calculations have more inputs, and time-stamps are less likely to miss extremes.

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