There is a new module named [Date Recur Field (repeating dates)][1] that can help you.

> Recurring dates, i.e. date repeat, for Drupal 8.
> 
> Provides a new field type that supports repeating dates via recurrence
> rules (RRule). For RRule compilation, php-rrule is used.

If you need integration with [Calendar][1] module you need to apply [Patch for calendar module][2]

I think that the module needs integration with the Datetime Range core module because for the moment to show a multi days event in Calendar you need the [Improve the Views integration for DateRange fields][3] patch.


  [1]: https://www.drupal.org/project/date_recur
  [2]: https://www.drupal.org/node/2820803
  [3]: https://www.drupal.org/node/2786577#comment-11860283