Prints of this theme (young woman caught in a rainstorm) were common during the Tokugawa period. Suzuki Harunobu, who produced this one, was perhaps the most accomplished master of this sub-genre. Although it may not appear so to the untrained contemporary observer, this print is erotic in that it is full of strong sexual imagery. The clouds burst forth with driving sheets of water, which (along with the wind) parts the woman's robes. And Tokugawa Japanese women did not wear underwear.
Additionally, the umbrella was a sexually charged symbol (for the phallus), which we will take up next. Notice that the rain is tending to push it into the woman, and, in this connection, notice the angle of its handle.
All of these points would have been immediately clear to many Tokugawa-period viewers, just as sexual symbolism in, for example, a TV ad is clear to (or at least has some sort of effect on) most contemporary viewers.
For more examples of similar prints, click on the thumbnail images below: