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I'm a little confused. RDU averaged normal today with the below values:

TEMPERATURE (F)
                     TODAY                      NORMAL       TODAYS DIF
  MAXIMUM         67                          64                 3      
  MINIMUM         36                          41                -5      
  AVERAGE          52                          52                 0       
 

If you average 67 & 36 you get 51.5 

If you average 64 & 41 you get 52.5

So they round the current temps up but round the average temps down. That's a scam, it should be 1 degree below normal today. 

Edit: after thinking about it, maybe the whole number temps they display are not the actual number of record; meaning maybe the average high of 64 is actually 63.6. ...or something like that.. 

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I'm a little confused. RDU averaged normal today with the below values:

TEMPERATURE (F)
                     TODAY                      NORMAL       TODAYS DIF
  MAXIMUM         67                          64                 3      
  MINIMUM         36                          41                -5      
  AVERAGE          52                          52                 0       
 

If you average 67 & 36 you get 51.5 

If you average 64 & 41 you get 52.5

So they round the current temps up but round the average temps down. That's a scam, it should be 1 degree below normal today. 

Edit: after thinking about it, maybe the whole number temps they display are not the actual number of record; meaning maybe the average high of 64 is actually 63.6. ...or something like that.. 

It's a weighted average. You can't just average the high and the low. You have to account for how long the temperature remained at each measurement, including all the values between the high and the low.

Sent from my Alcatel 6055U using Tapatalk

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2 hours ago, calculus1 said:

It's a weighted average. You can't just average the high and the low. You have to account for how long the temperature remained at each measurement, including all the values between the high and the low.

Sent from my Alcatel 6055U using Tapatalk
 

So basically they need a database to manage all the daily readings and scripting/programming to determine the weighted high and low. And what they report out to the public is generalized as whole numbers. 

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17 hours ago, FallsLake said:

So basically they need a database to manage all the daily readings and scripting/programming to determine the weighted high and low. And what they report out to the public is generalized as whole numbers. 

The high and low for the day are not weighted:  They are simply reported as the actual highest and lowest temperature recorded on the calendar day.  The average temperature for the day is what is weighted.  Wikipedia has a good article on weighted averages, and their basic example is quite easy to follow, I think.

Similar to Wikipedia's example of test scores, in weather, you can't just average the high and the low to get the average temperature for the day.  Here's why:

Suppose on any given day, the high were 60F and the low were 50F.  It would appear as if the average temperature should be 55F, right?  But, suppose that the low of 50F was recorded at midnight, and then the temperature quickly rose to 60F by 1:00 AM, before remaining a constant 60F for the rest of the calendar day.  Thus, for the vast majority of the day (23/24 of the day, to be exact), the temperature was 60F.  The average temperature for that calendar day would actually be much closer to 60F than it would be to 55F.  Assuming we only took measurements on the hour -- in reality, you could take them a lot more frequently -- then your average would be calculated in this way:

(50 + 60 + 60 + ... + 60 + 60)/24 = 59.58F

(There were 23 measurements of 60F in the above calculation.)

This is an extreme example, but I hope it helps illustrate the situation.

 

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4 hours ago, calculus1 said:

The high and low for the day are not weighted:  They are simply reported as the actual highest and lowest temperature recorded on the calendar day.  The average temperature for the day is what is weighted.  Wikipedia has a good article on weighted averages, and their basic example is quite easy to follow, I think.

Similar to Wikipedia's example of test scores, in weather, you can't just average the high and the low to get the average temperature for the day.  Here's why:

Suppose on any given day, the high were 60F and the low were 50F.  It would appear as if the average temperature should be 55F, right?  But, suppose that the low of 50F was recorded at midnight, and then the temperature quickly rose to 60F by 1:00 AM, before remaining a constant 60F for the rest of the calendar day.  Thus, for the vast majority of the day (23/24 of the day, to be exact), the temperature was 60F.  The average temperature for that calendar day would actually be much closer to 60F than it would be to 55F.  Assuming we only took measurements on the hour -- in reality, you could take them a lot more frequently -- then your average would be calculated in this way:

(50 + 60 + 60 + ... + 60 + 60)/24 = 59.58F

(There were 23 measurements of 60F in the above calculation.)

This is an extreme example, but I hope it helps illustrate the situation.

 

Thanks for the info. I understand and it makes since; they are truly getting the average high for the day. But I'm on the fence of saying just take the high and the low and going with those numbers. There's a lot of complicating factors in weighting values.  

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14 hours ago, FallsLake said:

Thanks for the info. I understand and it makes since; they are truly getting the average high for the day. But I'm on the fence of saying just take the high and the low and going with those numbers. There's a lot of complicating factors in weighting values.  

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Here are always complicating factors and too many more things than we realize.  Any time you see the word average you need to investigate how that average is figured for it to have much meaning.

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