last or in

What would you say if the summer in question were a past summer?

1- I was in Miami in summer.

2- I was in Miami last summer.

is 1 correct too? is there a differece in meaning?

I was in Miami this summer.

I was in Miami last summer.

I was in Miami in the summer.

I was in Miami the summer before last.

I was in Miami in the summertime.

I was in Miami the summer of 1994.

I was in Miami the summer the beaches were all closed because of shark-infested waters.

Pieanne wrote:

Not in the summer of 1994? (must be my mistake, sorry!)

I believe it is natural here to say either, Pieanne...or so it seems to me.