Time series and stl in R: Error only univariate series are allowed

Question

I am doing analysis on hourly precipitation on a file that is disorganized. However, I managed to clean it up and store it in a dataframe (called CA1) which takes the form a

Answer 1

I tried to explain the write way with a very easy example to avoid these kind of errors in another question, linked here:

stl() decomposition won't accept univariate ts object?