Why Black Spots Suddenly Appeared on Some Plant Leaves

What id the reason for black looking spots on leaves of my house plants it almost looks as if they froze but I live in Tucson. they weren’t there last night but they are there this morning. 🙁

Since I live in Phoenix, I know there is no way your leaves froze in our 100 degree weather. My thoughts are that they got burned by either the heat or direct sun. If your plants are close to any windows, move them away this time of year. The glass magnifies the heat and the intensity of the sun. Check during the day to make sure none of your plants are getting direct sun. As the seasons change and the sun moves, different parts of your house get the direct rays.