* καλοκαιρινή αγάπη (kalokairini agapi): This is a literal translation, meaning "summer love." It's straightforward and accurate.
* έρωτας του καλοκαιριού (erota tou kalokairiou): This translates to "love of the summer" or "summer's love." "Έρωτας" (erota) implies a more passionate, intense love than "αγάπη" (agapi).
* καλοκαιρινός έρωτας (kalokairinos erotas): Similar to the above, but emphasizes the summer aspect being directly connected to the love.
* καλοκαιρινή φλερτ (kalokairini flirt): If the "summer love" is more of a fleeting romance or flirtation, this translates to "summer flirtation."
The best choice depends on the specific situation. If you're writing a poem, "έρωτας" might be more evocative. For everyday conversation, "καλοκαιρινή αγάπη" is perfectly acceptable.