Posts by time of day (GMT)
Note that all times are taken as GMT (ie London time), regardless of where the user who posted is posting from. While it would be nice to adjust for local times of posters - it is practically impossible to do in any reliable way.
Anyway, the chart is kind of interesting given the differences in time zones around the world. I would have expected a much flatter graph - with the west coast of the US 8 hours behind GMT and the east coast 5 hours behind.
Given the majority of our users come from the UK and from the US, I expected the peak posting times to be longer.
For example, the middle of the peak period in this chart is 9pm GMT/London time, which is understandable - many people jump on the forum in the evening to post. However, 9pm GMT is 4pm in New York and 1pm in Los Angeles (and 8am in Sydney!).
With such a spread, I would have expected far less of a peak.
Visits by time of day (all visitors - both members and guests ... GMT+10)
The above chart uses Sydney time (GMT+10), and thus is about 10 hours out from where is should be. The chart shows peak visitors at around 6am Sydney time, which is approximately 8pm GMT - which makes more sense. I have set up a new view in Google Analytics to show this data based on GMT, but it will take some time to populate that data.