Here is the full list of all 40 Summer Catchers achievements.
Help musicians to put on a great show
Buy all outfits, cars and postcards
Find all stashes (co-op only)
Complete all mailings
Tame all pets
Find the Firework Rocket
Collect 1000 rainy mushrooms
Tame a chameleon
Reveal the Crystal Skull
Tame a robot
Bucket the Meteorite
Tame a goat
Tame a fox
Find the Casette Player
Tame a ferret
Win the Jar with fireflies
Collect 1000 mushrooms from totems
Chew some bubble gum (co-op only)
Play in co-op
Overcome a hill or a bridge. No boosters, no bubbles
Listen to the whole inventory song
Break down a car before a race (co-op only)
Catch the World Map
Use a bell to wake up a sleepyhead
Catch a bubble, a drum and a horn in one race
Tame an owl
Activate a secret code
Leave a race right after a crash
Receive the Bell
Overcome 5 obstacles in a raw in a bubble
Complete tutorial