In The Outsiders, sunrise and sunset are symbols of unity and connection. For example, when Ponyboy connects with Cherry at the movies on the topic of sunsets, he begins to realize that all humans are linked through the natural world. When Pony is confused and angry over Cherry's willingness to help the Socials before the rumble and after Bob's death, he uses the topic of the sunrise to diffuse the situation.
The sunrise is associated with a much closer connection between Pony and Johnny. The high point of this connection is when they watch the sunrise together from the top of Jay Mountain, and after Ponyboy recites the poem "Nothing Gold Can Stay" by Robert Frost. (More on that in Johnny's "Character Analysis.")
Johnny tells Pony, "I never noticed colors and clouds and stuff until you kept reminding me about them. It seems like they were never there before" (5.62). Seeing the dawn at this moment is, for Johnny, a truly new dawn, because his eyes open wide to the natural world. Sadly, he doesn't get to experience life through these new eyes for very long.
This is an important moment for Pony, because he's found someone who shares his vision of the natural world. He tells Johnny, "you ain't like any of the gang. I mean, I couldn't tell [them] about the sunrise and clouds and stuff. I couldn't even remember that poem around them" (5.65). This helps us understand just how hard it was for Pony to deal with his friend's death.