As with many of Hemingway's stories, critics tend to disagree over its meaning. Carlos Baker, Hemingway's first and most comprehensive biographer, suggests the story, like other Hemingway stories involving the relationships between men and women, is about a wife who longs for a more domestic lifestyle and that the cat in the story is a symbol of what the wife wants from her marriage. Her husband doesn't seem willing to provide those things. Even though he offers to go down and get the cat, the reader must assume that it's only a half-hearted overture and that he is preoccupied with relaxing on the bed and reading.
Similarly, John V. Hagopian theorizes that what the wife really wants is to be a mother and that the cat is a symbol of the child she longs to have. She very much wants to hold the cat in her lap and stroke it. Moreover, the rain which hampers the cat is a symbol of fertility. Hagopian points out the inclusion of the man wearing a "rubber cape." The "rubber" can be seen as symbolizing a condom, strengthening the idea that the rain is a symbol of fertility, especially when compared to drought, which also seems to sum up the couple's marriage. That the maid opens an umbrella to protect the wife from the rain further identifies it with fertility.
On the other hand, David Lodge, in "Analysis and Interpretation of the Realist Text: Ernest Hemingway's 'Cat in the Rain,'" posits that the rain is simply a symbol of the loss of pleasure and joy, in contrast to good weather, which brings happiness and creativity. The rain may also symbolize a bad point in the couple's marriage, and this seems to be backed up in the text when the wife indicates she wishes some things were different about her appearance and the husband seems to ignore her.