Final answer:
The speaker stops by the woods to watch the snow fall.
Step-by-step explanation:
The lines suggest that the reason the speaker in the poem stops by the woods is to watch the snow fall. The speaker describes the darkness of the evening and the quietness of the surroundings, with the only sound being the sweep of easy wind and downy flake. This creates a peaceful and tranquil atmosphere, which would make watching the snow fall a likely reason for stopping by the woods.
Learn more about Reason for the speaker stopping by the woods