plotting without straight lines connecting two intervals of data in a same day

Between 8.2hours to 12.5hrs there is no data and so a straight line appears.

How to avoid that straight lines connecting two sets of data of the same day?

Answer 1

[Walter Roberson]

Insert a nan into the both plot variables at that point.

You could also use multiple nan there -- so you could insert a nan for each time you expect which is not present. Only one nan is needed for plotting purposes, but sometimes one nan for each expected time is easier to deal with.