"Just In Time" is also known as "Webinar on top of hour". However, you are not limited to run webinar on top of hour only. "Just In Time" option is a repeating scheduler that has a range of options.
You can decide when it should run, you can choose from on top of next 5, 15, 30 and 60 minutes.
You can choose when it should run as well. For example, if you do not want to run it during the midnight, you can set "Between the times of" to 9:00AM to 9:00PM.
"Just in Time" runs in local timezone.