My sister is looking to get a DSLR so Im thinking about selling her my D3200 and upgrading but I dont know what would be a good choice. I really want something weather sealed to start.
I thought maybe a D7100 (or whatever the newest 7000 series is) but the D610 isnt much more. What do you guys think??

What glass do you have now? The D610 is good, but its focusing system isn't nearly as good as the D800. The D7100 would basically be a focus system upgrade alongside weather sealing and a couple other things. If that's what you want.

I think you should be moving to full frame, unless if you love shooting wild life.

I don't know how often you shoot or what you shoot but, I would grab the D7100 IMO since you can use all your DX lenses on it you currently have. unless you have no lenses and starting fresh lol.

I'll be looking at the D610 in the near future but for the casual shooter, D7100 is perfect.