If you’re getting your water straight from the tap, you should let it sit in a jug with the lid off for at least 24hrs. You will see the chlorine start to evaporate as the tiny bubbles start collecting near the top of the jug. (I use 1 gallon sized glass jugs you can get at any brewery) if you’re not testing the pH of the water you’re using, this practice will at least get some of the non-desired water containment’s out naturally. Let it sit in the sun if you want to kill any bacteria that may be in the water. Other than that, you need to get a pH tester. You can find a decent one on Amazon for less than$10. One thing I have learned, is that the pH of the water you are using is just as, if not more important than the pH of the growing medium, (assuming you’re growing in soil). Other than that, it looks like heat stress to me. Or a potassium deficiency. But make sure you check your pH before you start adding/taking away nutrients. Kinda like just going back to the basics, and check the small things off the list. If it’s normally around 100* where you are, (I’m in Santa Barbara and have a few outdoor plants that are doing wonderful) but my climate is a lot different than yours. Find a way to get those temps down or think of a screen/mesh type of material to place over the plant. It will drop the intensity of the light and make sure your soil isn’t overly saturated. Hope that helps... . I’m still learning as well, but have definitely had your problem before. Mine was heat stress with a slight potassium deficiency.