From Nookipedia, the Animal Crossing wiki
This is a list of recipes in Animal Crossing: New Horizons that may only be obtained during the summer season. Recipes that use Summer Shells as a material may only be obtained from June 1 to August 31 in the Northern Hemisphere, and December 1 to February 28 (or February 29 in leap years) in the Southern Hemisphere.
Recipes in Animal Crossing: New Horizons
|Includes data sourced from this Item Spreadsheet, compiled by 6480, noizhub, Ricky, chaiinchomp, saberslime, robotic_scarab, mollumisc, sunmarsh, kyrokey, obstinateRixatrix, jackiwi, Zalex, SuperHamster, kait, hyuum, Azarro, Czarcasm, cinnamon_swirlix, astronomyfortwo, Welcius, glowtopia, BriKun, Alyrei, dodocodes.com, StevieCoops, sneeze, Shiny190, TwistedPeach, LavaToaster, capstone, vmario, rocklamp, Alexis, Aeon, and PanchamBro.