I am looking to work on a winery this summer. I want experience within the viticulture and enology sector of the market. With that in mind, I realize that the summer season poses restrictions on getting experience with the grapes, since I will not be present for a whole growing cycle. Does anyone have any recommendations in terms of where the best place in the world would be to get experience in this field during the summer?

Forget summer. There's a reason the wineries are lightly staffed then. You want experience- go in the fall, or alternatively the spring.