Can not calculate monthly Standard Evapotranspiration Index


Welcome to the RStudio community!

Although you are providing us with the code and your data, just dumping the files on here will make it less likely that anyone will try to figure out the solution. The goal is to create a small example using a reprex. A reprex consists of the minimal code and data needed to recreate the issue/question you're having. You can find instructions how to build and share one here:

Also, its important to clearly describe / show an example of the expected output for a given input.

Good luck,