I was inspired to ask by the famous John Green quote:
if people were rain, I was drizzle and she was a hurricane
Is this a metaphor? Without the "if people were rain" it would be, certainly, but with it? Does it count as a simile?
A metaphor is a substitution of the normal word by another expression in a way that it is possible to see what normal word was replaced. In your example above there is no substitution of a word. If you say black gold instead of petroleum you use a metaphor.
Comparing people to rainfall, and contrasting their characters as : drizzle and hurricane, is a form of analogy. Richard Nordquist the grammar and composition expert for the website about.com writes:
An analogy is a kind of comparison that explains the unknown in terms of the known, the unfamiliar in terms of the familiar.
A good analogy can help your readers understand a complicated subject or view a common experience in a new way. Analogies can be used with other methods of development to explain a process, define a concept, narrate an event, or describe a person or place.
- “Ants are so much like human beings as to be an embarrassment. They farm fungi, raise aphids as livestock, launch armies into wars, use chemical sprays to alarm and confuse enemies, capture slaves. . . .”
Although I would still argue that similes are metaphors, here's what Fowler says in Modern English usage:
"It cannot be said that every simile is a metaphor, and vice versa; it is rather that every metaphor presupposes a simile, and every simile is compressible or convertible into a metaphor. There is a formal line of demarcation; the simile is known by its 'as' or 'like' or other announcement of conscious comparison...."
In the original sentence above, "if people were rain" announces a conscious comparison, which makes what follows a simile.