Astringency in cucumbers is typically caused by inadequate moisture and high heat. Be sure you really water the heck out of them in this kind of weather, even if you don't think they need it.

Oh, I should add, if you peel them and slice or cut into quarters, then soak in ice water with about a half teaspoon of salt and a tablespoon of cider vinegar per half gallon of water for about 20 minutes, then rinse and soak again in clear water for 20 minutes, it will get rid of most of this and make them much less astringent when you eat them.

so watering them more often should fix the rest of the crop?