calculated column weather conditions

HI everybody, please assist.

I'm trying to establisch if certain weather conditions are rising. I've downloaded data from several weatherstations.

Given example: number of times "75% of 21 days more than 0,5 mm rain" ocuured in data of weatherstation. Can it be done? How?

Thank you

https://drive.google.com/file/d/14DTdUmVEyJPsbtUEGtwWS5k_tthZSybc/view?usp=sharing

# TX        : Maximum temperature (in 0.1 degrees Celsius)

# RH        : Daily precipitation amount (in 0.1 mm) (-1 for <0.05 mm)

#STN       : Weather station

PER (several)         : Boolean within relevant period