There is nothing like a garden! You've got it bad, girl!!
Watering every day isn't a good thing because you might not be really soaking the soil down, just getting the top. This means the roots may not grow deep enough. Once a garden is up and running (not
seedlings any more) a good thorough soak once a week is better than watering every day.
In my little humble opinion, mulch is the most important thing you can do to help retain moisture. My preference is straw or hay-- like the kind you used for halloween displays. Don't use pine straw if you can help it because over time it lowers the pH of the soil, but in a pinch, for one year, even pine straw would be better than nothing. Straw is good because it decomposes pretty quickly (adding organic matter which holds in moisture), holds water itself (to cut down on soil surface evaporation) and it's light colored-- it reflects the heat keeping the soil cooler. (This isn't good when you're starting
seeds, but you're well past that.) You can keep adding straw through the season, too.
This fall, you can just till the straw into the soil, and that will help a lot next year.
In short, anything can you can mulch with is the first step. Compost if you have it is excellent mulch, too. Even newspaper will work. It will dry out, but it would help keep the soil moist.
I've used soaker hoses in the past but didn't care for them. And if you do use them, they go under the mulch!
Two things about the droopiness. What matters is what stuff looks like in the morning. Like you say, who could blame them in the heat of the day? If they're not perky in the morning, though... .
I don't know what the situation is there where you live, but if your squash look great today, and tomorrow they have just keeled over and watering doesn't help, you have a problem. Let's hope it doesn't get to that!
Yeah! It's raining. OOPS. I left the truck up at the shop. Dang.