if you have ticked to use calc rain in the weather station type setup
then WD uses the value
“precip_total_24h”:9.522
in the weatherflow3.txt file
I tested, using the latest update (you do not say if you have that) and if I increase that value (mm) then the value in WD goes up
is that value in that file increasing when you like create rain?
there is also debug info in WD under view, debug info