This hadith says nobody knows when it will rain. This is false. We have weather forecasts which generally predict climate conditions correctly.
Narrated Ibn `Umar:
Allah’s Messenger (ﷺ) (p.b.u.h) said, “Keys of the unseen knowledge are five which nobody knows but Allah . . . nobody knows what will happen tomorrow; nobody knows what is in the womb; nobody knows what he will gain tomorrow; nobody knows at what place he will die; and nobody knows when it will rain.”
Sahih al-Bukhari 1039
Vol. 2, Book 17, Hadith 149