Microsoft has published the release schedule for its Edge browser, showing the targeted weeks that it plans to release the browser in the Stable and Beta channels. It goes up to Edge 89, which is slated for release in the Stable channel the week of March 4, 2021, while that will roll out to Beta the week of February 1, 2021.
The two channels are a month apart, and they're updated every six weeks, so there are two weeks between when a new Stable version rolls out and when the next one is promoted to the Beta channel. For example, Edge 84 rolled out on July 16 to the Stable channel, so Edge 85 will roll out to Beta the week of July 27.
The dates shown aren't surprising, but it's nice that Microsoft finally published something. With the two other channels, Dev and Canary, it's well known when these builds are rolling out. Canary is daily, while Dev is weekly.
Note that these are target dates, of course. Microsoft develops Edge along with the Chromium release schedule, so if the Chromium release schedules change, so do the ones for Edge. In fact, this is exactly what happened with Edge 82, which was canceled.