You can get information about future acquisitions over an area through https://spectator.earth either APP or the API. It parses most up to date acquisition plan available for Sentinel-2. No calendar view though, just a timeline.(disclaimer: I co-created it)
Acquisition plan for Sentinel-2 has a longer time span than the one for Landsat-8, so you’ll be able to predict the future a bit more. S2 plan covers 10-15 days while Landsat-8 is around 3 days at most.