##Java 8, <strike>313</strike> <strike>300</strike> 299 bytes##

    import java.time.*;()->{for(int c=0,h=LocalDateTime.now().getHour(),m=LocalDateTime.now().getMinute(),i;;)if(c>30){c=0;String l="",u,d;for(i=0;i++<60;)l+="-";u=l.substring(0,m);d=l.substring(m);System.out.println((h<10?"0":"")+h+" "+u+"\n"+(h<9?"0":"")+(h+1)+" "+d);}else{c++;System.out.println();}}

This only updates every 30 iterations of the while loop.  The other 29 iterations just print new lines.

**Updated**

Saved <strike>13</strike> 14 bytes due to Kevin Cruijssen's help! Thanks!