Count numbers of times within hours

What's the formula for counting the number of times something happened during a certain hour of the day?

For example, if I want to take the collumn below and say there were two occurences from 2:00 to 2:59 and so on for each hour of the day (1:00 to 1:59, 3:00 to 3:59, etc.).

21:29:00
15:19:00
14:30:00
23:30:00
14:56:00
21:41:00

Here's one way, assuming your times are in A1:A100.....

Put the time 00:00 in cell C1 and in C2 use the formula

=C1+"1:00"

copy down to C24

Then in D1

=SUMPRODUCT((A$1:A$100>=C1)*(A$1:A$100<C1+"1:00))

format column C as hh:mm and column D as general......