For me the clearest answer to this is Once Upon A Small Town. It’s a short and cute little show which might be just the thing to jump-start your summer. It has a distinct summer setting and happens almost completely in the countryside (as the name would suggest). The leads are great and actually talk about their feelings (a conversation that the ML has with his ex is one of my favorites in the whole drama) and there are puppies just as a bonus! If screechy ajummas annoy you, feel free to skip through their scenes - you won’t miss anything relevant.

My favorite Summer vibes dramas are Twinkling Watermelon and Racket Boys (beautiful countryside locations).

And if I can suggest some C-dramas: My marvellous fable, Meet Yourself and When I fly towards you.

Coffee Prince :)
Lots of outdoor summer fun.

Extraordinary You is top of the list for me - visually dazzling with bright, saturated summer colors and lush flowers.

The Matchmakers (LOL, I'm really not trying to sell Rowoon here) has lots of outdoor scenes with fields in full bloom, footpaths through shady groves, and warm summer nights.

See You in My 19th Life is not the greatest drama, or at least the most coherent ending, but it's very summery - cute dresses on the FLs, linen suits, swimming pools, flower gardens, flying insects buzzing the cameras as they film outdoors.

It has all four seasons, but if you want to see people sweating and wilting in relentless heat, it's hard to beat the summer scenes in My Liberation Notes.

Lovers of Haeundae is a 2012 South Korean television series set in Busan (Haeundae refers to the city's famous beach).

Just about anything filmed on Jeju Island (Welcome to Samdal-ri, On the Way to the Airport, Our Blues, High Class, etc.)

Hotaru no Hikari and Suika (Watermelon) are love songs to summers in traditional Japanese houses. The first one is a rom-com and the second one is a comedy/slice of life. Summers in East Asia are terribly humid and sticky and they always warn you not to visit in summer but these dramas show the beauty and charm of the season too. Summer months are magical in Asia.

The beginning of "Lovestruck in the City" is all Lovestruck on the Beach. Running around in bathing suits, serving food from small beach ... cafés or what you'd call then, ... and surfing. Even making a surfboard.

Tbh, I'm not sure if these are summer dramas or if they're just so bright and fun that they remind me to that time of the year, but at least one could be, right?

Ho Gu's Love
The Best Hit
Reply 94
My Beautiful Gong Shim
Run On
Fight For My Way

Maybe I'm weird, but I seem to take no notice of the seasons in dramas.

I do, when it is a plot point, or something that makes me uncomfortable, or doesn't make sense (like an actress visibly struggling with heat, or leads trying to sell a confession and kiss while freezing to death wearing three layers of coats and looking purple and blue...) but I don't just go and notice that oh it's summer, or winter.

I know it was summer in Scent of a Woman, firstly because of a specific plot point, and secondly because there were many many beaches and pools scenes, and Kim Sun Ah wore some of the lightest airiest clothes in dramaland. BUT! SoaW is neither easy breezy, nor filled with light and sunshine...

I'm used to California summers, so nothing in kdramas really look like summer to me - I just see winter and not winter. But there is surfing in Hometown Cha Cha Cha. And I think there was a beach trip in Marriage, not Dating? And some island frolics in Haeundae Lovers.

Our Beloved Summer had a great summer setting on their high school days scene. I love the color palette.

25-21also had similar vibes on the earlier episodes when the main characters were in their teens.

Twinkling Watermelon also had wonderful summery scenes when the characters were transported back.

School 2017 had a wonderful summer vibe. Oh the freshness of youth.

I see a recurring theme.

Meet Yourself (cdrama) also had a summery feel to it. I love all the scenes in Yunnan.

The Frog

I love this prompt! I keep a list I call "The Four Seasons" where I put dramas I've enjoyed that really feel like/show seasonal weather. Here's what I've got:
• 30 But 17 (cicadas; hot weather!)
• Extra-ordinary You (summer breeze!)
• The Best Hit
• Pegasus Market
• Call it Love (cicadas!)
• Once Upon a Small Town (sunshine!)
• Rainless Love in a Godless Land (lots of rain!)
• Like Flowers in Sand (cicadas; hot weather!)
... and See You in My 19th Life (summer rain)

I’ll go with Twinkling Watermelon. It’s hot with the passion of the youth, but cool with the love of family and friendship that feels like summer breeze.

I don’t know why but these I always *crave* to re-watch every single summer:

Coffee Prince
ML Sam Soon
The Greatest Love
Fated To Love You
Fight My Way