If you click change Visitors Overview report from the default Day view to the Hour view, you might not get what you expect.
What the report shows is not an aggregated view by hour for the time period selected, but rather the number of visits that occurred during each hour on each day.
Because this would equate to 720 individual data points for a 30-day month, this view seems to be practical only if you want to pinpoint the most active points in time over the course of that month.
This view can be more usable if you narrow the date selection down to a day or two; in this case, there are few enough data points on the main over-time graph to be intelligible.
But what if you want a consolidated view of hourly activity?
For this, you can easily set up a Custom Report using the Hour dimension. (The Hour of Day dimension, which provides the same non-aggregated data as the Day view in Standard Reports, won’t do the trick.)
It’s better to select Flat Table instead of Explorer format, since this suppresses the over-time graph, which would unhelpfully display only visits by day for the time period selected. If you want to chart the 24 aggregated hourly data points, you can export from the Custom Report into a spreadsheet and create a line or column chart there.
As a related note, if the time zone indicated in your profile settings is not correct for you, you can change it at any time, but keep in mind that this change will not apply retroactively to data that Google Analytics has already captured.