Answer:
He calls the current time period a "season,"
implying that it will give way to a new season.
Step-by-step explanation:
Martin Luther King Jr in his "I Have A Dream" speech made use of metaphors to make his speech more effective, and this was one of those examples.
Here, he compares the legitimate anger of the African Americans and their agitation for equal rights to the heat of summer and freedom and equality as to autumn which invigorates.