Python pandas how do i write the where Klausel with two dataframes and one merge

Question

import pandas as pd

df1 = pd.read_csv("jojojo.csv")

df2 = pd.read_csv("kokoko.csv")

df3 = df1.merge(df2, how='inner', on='Ice')

I want to create the where klausel does it need to look like this? is the coding grammar right?

pd.df3.where(df3['Ice']>90)