A report from BGR claims the third beta release of iOS 8 will not occur until July 8th. That would mark a three week timeframe between it and Beta 2, released last week.
Apple commonly begins seeding versions of its major new iOS versions on roughly two-week intervals, moving to three-week intervals later in the testing period as work progresses. For example, with iOS 7 last year, the second and third betas arrived two weeks after their predecessors with the fourth beta shifting to a three-week interval. Apple did, however, then follow that with several intervals of around a week as it pushed out an urgent bug fix.
iOS 6 followed a similar beta release pattern, with a two-week interval between betas 1 and 2, followed by three-week intervals between betas 3 and 4.
