record , save and filter rainfall data to show only for the specific month

good day everyone.

i want to record rainfall data for the entire year by months.
i already created a dropdown menu to select the month.
the challenge I have is that the data is static.
For example I select Januaryand record rainfall data for all the days of January.
When I select february, the cells already has the data I entered for January.
I want when I select a new month, the data for previous month is stored but does not show anymore to allow me to enter data for the new month and if I select a month where previous data was entered, it must show rthat inforamation.
Can anyone help me fix this please. Any guidance will highly be appreciated.
Much love.