Finding Daily Averages for Values in Large File

@Spitzer, Liz ,

According to the images, is the data of "WVHT" the wave height values?
If so, I made a brief sample, and I would get an average value for every day via following 2 ways.

Sample:

1

• Right click all data > Get Data from Table/Range > check the range of data which should be include headers, select the box of "My table has headers".
• Select Date column > Home > Transform group > Date Type: Date > Replace Current.
• Then go to Group By > Choose "Basic" and group by “Date” cloumn, name a new column (Here I call it as "Average Value"), and then choose "Average" as Operation and "WVHT(m)" as caulation column > Click OK.

• Then I get the result below.

Click File > Close & Load To > Table > Choose New Worksheet or Existing Worksheert to show the table > Click OK.

2

If you do not want to use Power Query, you may also use Subtotal.
Select the data, go to Data > Outline group > Subtoatl, set as the following picture. If needed, you may also click the "Level 2" to just show the average value.

Any misunderstanding, please let me know.

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