Google-sheets – Google Sheets time sorting chart

I'll describe the process in stages. Here is a command that returns a table with high price on every day within the last 26 weeks:

=GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY())

Output:

+-------------------+----------+
|       Date        |   High   |
+-------------------+----------+
| 2/2/2015 16:00:00 | 533      |
| 2/3/2015 16:00:00 | 533.4    |
| ................. | .......  | 

Since you only want the maximum of these numbers, let's add a QUERY selecting the maximum of the second column:

=QUERY(GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY()),"select max(Col2)")

Output:

+----------+
| max High |
+----------+
| 678.64   |
+----------+

This may be already good enough for your purposes. If you want to get rid of the column header "max High", end the query string with label max(Col2) '':

=QUERY(GOOGLEFINANCE("GOOG","high",TODAY()-26*7,TODAY()),"select max(Col2) label max(Col2) ''")

Output:

+----------+
| 678.64   |
+----------+

Perhaps one of the following may suit:

The !st coffee column is formatted as Number, Time and the chart set to take the formatting from the source. What may be a little confusing is that the vertical axis runs from .25 to .75 (In the right-hand chart, with minor gridlines count set to 2 ie hourly).