The only way you can be clear about the 'this summer' meaning is to use the words 'this summer'. The only way to be clear about the 'any summer' meaning is to say something like 'during the summer one year'.

Student or Learner
Which article should be used in:
1) I'd like to visit Greece in the summer/summer. (I mean any summer.)
2) I'd like to visit Greece in the summer/summer. (I mean this summer)
The only way you can be clear about the 'this summer' meaning is to use the words 'this summer'. The only way to be clear about the 'any summer' meaning is to say something like 'during the summer one year'.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
So it can mean any summer or a specific one, can't it?
1) I plan to travel to Europe over the next few years. I plan to visit Greece in summer.
Does it mean any summer?
2) - Do you have any plans for your holiday?
- I hope to go to Italy in summer.
It is "this summer". Is it OK without "the"?
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.