Strictly speaking, crontab schedules define "points" in time when the specific actions are triggered, whereas it seems you need a broader "range" or "set" of time spans.

It might be overkill, but I think you should be able to accomplish this with the DateTime modules.

For example, take a look at DateTime::Event::ICal... Using the ICal format, you could express your rules as:

  my $incident = DateTime->from_epoch( time() ); # your data here
  
  my $ok_down = DateTime::Event::ICal->recur( byday=>["su"], byhour=>[
+6, 7] );
  
  unless ( $ok_down->contains( $incident ) {
    # notify 
  }
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