I used to spend all my summers in Japan to visit my dad, who lived there.
Tokyo is a great, lively city that is full of great food and casinos! they are crazy over there for pachinko, which is a type of gambling place.
If you're American, then why are you becoming a doctor in Japan? Or is that just for college?
Anyways, in the summer it's very hot and humid there, kind of like Florida, but in the Winter's it gets very cold (but not a dry cold.) At least that's what my dad told me, I didn't go there in the summer. You will find that the people are very different, more self diciplined and serious, and that there sense of humor is way different! They have amazing food though! And Tokyo is full of technology and cool, hip restaurants and bars.
You'll enjoy it! and take trips to different parts of Japan! like Okinawa! Hope that helped!