The past couple of weeks (ever since it got over 90 degrees) there have been a lot of new brown spots and areas just shriveling up and dying (they don't even turn burn, just turn hard and die off). I know you shouldn't aerate until spring or fall, but I think it'll help a lot to do it now. I have very dense clay soil, and in some places I can't even shove a screw driver more than a couple inches into the soil (mainly the areas where grass is dying). Should I use a core aerator or spike? It looks like core is the better choice, and does a much better job. I'll just be using a little hand held one, it's only like 1,000 sq ft.

And I water it plenty, 10 minutes at night, 10 minutes at sunrise. The soil's usually still moist at midday. Please let me know what I should do!

As for eventual aerating, core is definitely the way to go with clay. I would also recommend topdressing with compost after aerating.

I don't think it's possible to Not water at least once a day. Everyone I've talked to water's twice a day here...100+ degrees for 3 months out of the year takes a toll on the grass!

When I bought my house, I could water 15 minutes per zone. After that, it would start to run off. So I started watering 10 minutes per zone, waiting an hour, then repeating. But I switched from 3x a week to 2x a week. Eventually, I got to 25 minutes per zone, 1x a week. I now water only three times a summer, but that's because I'm using non traditional grasses in my lawn.

EVERYBODY in my neighborhood waters every day (except for me). When I first moved here, everybody except me watered 3x a day. They did that because EVERYBODY knew you had to.

Watering restrictions went into place that limited watering to certain hours. They started watering 1 or 2 times a day and lawns were still green. I was watering 3x a week, even before the restrictions.

I'm curious about your grass choice. Tall fescue is a cool season grass. Bermuda is a warm season grass. I zone 8-9, I think you should pick one and go with it. Bermuda is known as an aggressive grass, but one that requires a lot of input. It also likes to be kept short. Tall fescue is a cool season grass that needs less nitrogen and likes to be mowed high.

However you have hardpan. As stated water for 10 minutes, wait for it to soak in, water again, and repeat process until the soil is saturated down to a depth of 6 inches.

You have to accept the fact the ground is not a welcome mat out to plant in it. So first thing is to change its attitude.
Clay soil aside, you have to inject into it what will change its attitude to welcome water....and hold it.

Its old thinking....but its as viable today as it was before the Oklahoma Dust Bowl caused change of thinking how to farm.

Its called "organic gardening".
Do research into what forms of "organic matter" is available in your area.
Injecting organic matter into soil invites moisture to stay, yet allows for good drainage.
Watering a ground that puddles after so little is given should be a clue as to the ground's ability to absorb it down deep enough to invite strong roots of whatever you're trying to grow. Short roots, hot sun, is without doubt, the reason the ground is what it is. There is no plant life able to withstand practically surface growing in a climate with temperatures you have. So make the change to the soil first, then plant what will grow in it.

You will need to use a tool...a rototiller, first to break up the hard ground, then it will help to mix the organic material down deep. Six inches is the usual depth --minimum..(for soil not in bad trouble, 4" is a general rule).so for your particular problem I suggest you think 12" deep. This brings on a problem...money. Some organic matter such as good compost does not come cheap. So you might call around and ask prices for the amendments you choose. Whether peat moss should be included or not is up to you; maybe there is something other than peat that will suffice. But peat moss is a common addittive to soil to invite moisture retention and helps the soil's make-up.
Depending on just how much ground such organic matter has to amend, it is the only way you will ever cure the problem.

If deep and infrequent watering does not work, then you have the wrong grass. Fescue is the wrong grass for the Mojave desert. Yes, I realize it is an extremely popular grass, but when trying to grow it in the desert, it will consume all the water you can give it. If water was prevalent, it would not be a desert. It would be much better to select a variety of grass that is strongly adapted to your area. bpgreen can help steer you in the right direction but you will have to do some ground work with your county extension agent.

Despite what the previous poster suggests, you will NEVER need a rototiller to prepare your soil. There is no six-inch 'usual depth' for preparing soil for turf at the homeowner level. After reading comments and complaints on this forum and others for 10 years, I'm convinced a rototiller will destroy your soil structure. In three years, when the structure finally reestablishes itself, it would leave you with a bumpy surface.

You can create a deeply organic soil by working entirely at the surface without aerators or tillers. Look in the Organic Garden forum and find the FAQs. At the bottom of the list is the Organic Lawn Care FAQ. It will get you started. In the case of organics, more is better until you get up to about 80 pounds per 1,000 square feet. Beyond that point you have to start thinking about whether you might be smothering the grass. If you want to get your organic numbers up fast, apply alfalfa, soy bean meal, or whatever you can get, at 20 pound per 1,000 square feet every week all summer long. It will cost you a little more but it has been shown to work.

If you are going to that extreme, then before you put all those organics down, you might want to invest in a good soil test from Logan Labs, not your local extension service. Again, this is after reading for 10 years. Logan Labs has an excellent reputation. Local extension service has, at best, a reputation for having poorly motivated/educated personnel and too often incorrect test results. The Logan Labs test will enable you to tune up your micro nutrients better than any extension service test.