So, winter has Cat Caps, Winter Hats, and Tam o' Shanters for head slot items. Two have 120 insulation and sanity boosts, while one has 60 insulation and a minor sanity boost.
What does summer get? Straw Hats, Ice Cubes, and a Dumbrella. One is easy to make, another degrades fast & slows you down, while the last you can usually only get one of per year. One has a mere 60 summer insulation while the others have 240. (One cools you down though, so its insulation is a little redundant.)
I suggest we add a Sombrero to the mix to help balance this out. The Sombrero would cost 12 Cut Grass, 3 Silk, and 4 Papyrus to make, and would offer 120 Summer insulation while boosting sanity by 3.3 per minute. With a Sombrero, players can finally have an in-between item they can make with a bit of work, without fighting over the Dumbrella for cane usage. And the skins! The variety is high. Please think it over and I hope you enjoyed reading this!