in summer in the summer

[ripley]

Hi, is there a difference
in the summer I usually...
in summer I usually...

[svartnik]

Originally Posted by ripley

Hi, is there a difference
in the summer I usually...
in summer I usually...

I cannot think of a case where I would distinguish between in summer and in the summer.
Maybe here:
In the summer of 1969.
In summer of 1969

[engee30]

Originally Posted by svartnik

I cannot think of a case where I would distinguish between in summer and in the summer.
Maybe here:
In the summer of 1969.
In summer of 1969

Just like svartnik points it out in his post, in the summer is more specific; talking about a general situation/state/event, in summer and in the summer are interchangeable:

In (the) summer I usually spend my free time sunbathing at the beach.