You can use formulas to get counts if that is your goal.
If you want to just look/filter by a time period, the autofilter method for one period will suffice.
Or, you can do both. IF you wanted multiple intervals filtered at once, toadstool's helper column method will be needed for autofilter or a criterion table for the advanced filter method to filter-in-place.
If filter is needed for each time period, a macro for each interval period would do it quickly. Of course adding the criterion manually is easy but not as-fast-as a macro.
Another option might be to use conditional formats. That would show the time periods but it will not be continuous. It might give you a good feel for the data. A sort might be a good way to visualize the data when combined with conditional formats.
Once you decide on the goal(s), you can post a link to a shared site like dropbox. The simple file would have obfuscated data if needed. The file might make helping you easier and more tailored to your data.