I am trying to count the # of times a value occurs in a column, the column
format is dd/mm/yyyy hh:mm AM/PM and i want to count all occurrences between
7am and 8am, 8-9, 9-10, etc and have utilized this formula

=SUMPRODUCT((HOUR($I$15:$I$350)=7)*(HOUR($I$15:$I $350)<8))

and it seems to work, however with the midnight to 1 am

=SUMPRODUCT((HOUR($I$15:$I$350)=0)*(HOUR($I$15:$I $350)<1))

it is returning the blank cells as well how can i adjust this to not count
the blank cells, also is there an easier countif formula that could do the
same thing?
Thank You