We had summer deployments each year so I never was able to experience summertime in Japan (or climb Mt Fuji ><). But other times of the year in Yokosuka were nice, and not too cold in the winter.
I know what you mean with Konbinis. I used to stop in every day on the way to work and grab a onigiri and a lemon soda. The only store in the states that rocks as hard is Wawa.