What's the tone in "The Storm" short story by Kate Chopin ?

Concerning your question about tone in Chopin's short story, "The Storm," tone is the speaker's attitude toward the subject of the story. 

The subject of the story is a woman's need and right to fulfill her desires, the same as society has allowed men to do for centuries.  Chopin is addressing the issue involving the fact that males are often seen as manly, macho, successful when taking part in amorous affairs, while women are labeled, condemned, and sometimes punished for doing the same thing.

The speaker's attitude toward that issue/subject is sympathy.  The tone is sympathetic. 

The speaker seems to understand these issues and sympathizes with female behavior in the story.