When we think of point of view in terms of literature there are three different types that are used mainly by authors: first person, the omniscient point of view (all-knowing) and third person limited. The third person limited point of view is interesting because we still have an exterior narrator who is outside of the story looking in on the action, but this narrator chooses to tell us the story from the point of view of one character alone. The narrator is still exterior to the tale, so it is not first person point of view, but this narrator focusses on one character alone.
It is clear from the very first paragraph then that the third person limited point of view is the one that Bradbury uses in this excellent short story. Consider the first paragraph:
The sign on the wall seemed to quaver under a film of sliding warm water. Eckels felt his eyelids blink over his stare, and the sign burned in this momentary darkness... A warm phlegm gathered in Eckels's throat; he swallowed and pushed it down.
Note how the story is narrated in the third person, but we are still focussing on one character alone. The benefits of this approach is that we are able to remain exterior observers to the tale as we follow one character and we don't know what the other characters' are thinking and feeling, except through their words. This is crucial in this story as we are never aware until the end how serious Travis is in terms of the punishment he will visit on anyone who does change the future. Hearing the "sound of thunder" from Eckels's perspective alone at the end of the tale seems to emphasise the horror of his untimely end.