Sporadic Missing Dates In Time Series Data

Please take a glance at my missing dates below. Sometimes it’s one date and sometimes several dates in a row.

These dates were derived via Groupby Mean of how ever many properties closed each month of each year. Obviously, if nothing closed that month, then no mean date derived.

I found this workflow from several years back, but was wondering if there’s anything simpler in recent times. I’m using Missing Value Linear Interpolation for numeric missing data, but I can’t anything like that for dealing with missing dates.

https://forum.knime.com/t/adding-rows-with-missing-dates-and-0s-for-time-series-analysis/9606/3

I’m not worried about extreme accuracy for splitting the distance of exact days or anything. If I had some system to state the 15th of each missing month (and year), that would be enough to fill the gaps for a time series presentation of the data.

Thanks for any suggestions you may have.