As a mnemonic I use two holidays to help me remember to plant and harvest my garlic each year. Halloween is for planting (this is easy due to the legends of vampires being repelled by garlic). July 4th is for harvest (think fireworks of flavor!)
This year is different. We have had rain, rain and more rain throughout June. The soil is thick with moisture. You are supposed to let the soil dry out to make the harvest easier, but with the leaves on some plants withering fast, a "wet harvest" may be in the cards.
Remember, you need a few green leaves in order to peel the dirt from the head. So don't wait too long if you want to bring your garlic in for dinner.