What ia the episode when Hikaru helps Haruhi through a storm?

You're likely thinking of Episode 12 of Ouran High School Host Club, titled "The Storm". This episode focuses on Haruhi struggling with a difficult situation involving her father, and Hikaru, along with the rest of the Host Club, steps in to help her through it.

While the episode doesn't feature a literal storm, the title refers to the emotional storm Haruhi is experiencing. The Host Club's support helps her weather this challenging time in her life.