Continuing to use your existing database,$$let$\text{'}$s make some changes to it:

Directions

Create a copy of your database $($You can do this in Python or whatever way you prefer$)$

If you used inches for your original precipitation, read them in from your database and replace them with millimeters.$$ Do the opposite if you started with millimeters.

Make the date on each of your readings $1$ day earlier $($because you realized the reading date was actually the day after the actual precipitation$)$

Delete one of your cities and all of the data associated with it$.$