I have a bunch of pairs of Under Armour thin gloves - basically the thickness of heat gear, but with honey comb silicon grip on the palm. They're thin enough that I can wear them in 70degree weather, but enough glove to still offer a bit of warmth when I pull them out of cold weather glove when the mercury drops.

Fingerless gloves are another good option for warmer weather. They can be very warm when you make a fist, but let heat escape readily when you open your hand. I have some under armour glommits that work well this way, as well as an old thick-knit cotton pair from about 20yrs ago that I use.