import pandas as pd

rainPerMont = {}

def rain_month():
    df = pd.read_csv("MOCK_DATA.csv", sep=',')
    count = 1
    while count < 13:
        rainPerMont[count] = df.loc[pd.to_datetime(df['Date']).dt.month == count, 'Rain'].sum()
        count+=1

    print(rainPerMont)



rain_month()