Games like Summer Days
Games like Summer Days include Our Life: Beginnings & Always, I Wani Hug that Gator!, LoveChoice, Refind Self: The Personality Test Game, and Florence. We matched them by the tags players give Summer Days on Steam (Choose Your Own Adventure, Visual Novel, Dating Sim, Casual, and Female Protagonist): closest matches first, and among equally close ones the better-known games.

Our Life: Beginnings & Always
Shared: Visual Novel · Dating Sim · Choose Your Own Adventure

I Wani Hug that Gator!
Shared: Visual Novel · Choose Your Own Adventure · Dating Sim

LoveChoice
Shared: Dating Sim · Visual Novel · Romance

Refind Self: The Personality Test Game
Shared: Visual Novel · Female Protagonist · Interactive Fiction

Florence
Shared: Casual · Female Protagonist · Visual Novel

Doki Doki Literature Club Plus!
Shared: Visual Novel · Dating Sim · Cute

Senren * Banka
Shared: Visual Novel · Dating Sim · Casual

Far Away
Shared: Visual Novel · Choose Your Own Adventure · Female Protagonist

ATRI -My Dear Moments-
Shared: Visual Novel · Dating Sim · Casual

Hooked on You: A Dead by Daylight Dating Sim™
Shared: Visual Novel · Dating Sim · Choose Your Own Adventure

Vampires' Melody
Shared: Visual Novel · Casual · Dating Sim

Love Is All Around
Shared: Dating Sim · Visual Novel · Interactive Fiction

The Hungry Lamb: Traveling in the Late Ming Dynasty
Shared: Visual Novel · Interactive Fiction · Dating Sim

Class of '09: The Re-Up
Shared: Visual Novel · Choose Your Own Adventure · Female Protagonist

Love Curse: Find Your Soulmate
Shared: Visual Novel · Dating Sim · Female Protagonist

Sweet Home
Shared: Visual Novel · Female Protagonist · Dating Sim

Lucy -The Eternity She Wished For-
Shared: Visual Novel · Dating Sim · Cute

Otaku's Adventure
Shared: Dating Sim · Visual Novel · Funny

Volcano Princess
Shared: Female Protagonist · Dating Sim · Visual Novel

Mirror 2: Project X
Shared: Visual Novel · Female Protagonist · Interactive Fiction

Marco & The Galaxy Dragon
Shared: Visual Novel · Female Protagonist · Casual

1 to 1 humanoid edible toys
Shared: Visual Novel · Dating Sim · Female Protagonist

Letters From a Rainy Day -Oceans and Lace-
Shared: Visual Novel · Female Protagonist · Dating Sim

The NOexistenceN of you AND me
Shared: Visual Novel · Interactive Fiction · Cute