They are growing in the garden beds. everything else is thriving! For example, my pepper plants are already even growing some peppers however I noticed that my squash and zucchini are wilting. I actually have not watered them myself in a while because it has been raining a lot in my area.. the last time it rained was a couple of nights ago I believe on thursday night it poured pretty hard just for a short period but then stopped. I have no idea if this is the result of overwatering or under watering.

I think it's under.

It looks like underwatering to me too. You may want to water them in the morning and see if they perk up. But, by the end of a hot, sunny day, they will probably look like that again.

When it's hot and sunny, I'll water the squash every day.

Edit to say: Especially if they are growing in a container, you will need to water more often than if they were growing in the ground.

@NewGardener95 , is the surface covered with a light mulch or is that the soil surface? My experience with soils containing that large of pieces of organic matter is that they do dry out fairly quickly.

You might want to invest in one of these. Very handy device for container plants...
LINK = Moisture Meter

But (there's always one, isn't it?), you said your other plants are thriving. Is everything planted in the same type of soil?

Stick your hand down into the soil and see if it's moist. About as simple of a moisture meter as you can get!

I see that you've got small fruit on a plant or two. There are SBV (squash vine borer) that can cause something like you see...but, the leaves and stems will start collapsing because the borer's have blocked off water uptake in the stems. You're look mostly healthy, though. I do see a tinge of yellow on a couple of leaves but nothing overwhelming.

Stick your hands in there.

@wildflowers Thanks! When watering a container, how do I know when to stop?

@intheswamp there was some mulch in the topsoil I used (I think) and I also mixed w/ compost

@intheswamp When watering a container, how do I know when to stop?

Does your containers have drains on them? If so, I wouldn't worry too much about over watering. In a normal situation it is stated that vegetables need 1" of water each week. In a container, probably more. Being as squash fruit is a high percentage of water you should take that in to consideration. And, in your environment 1" may simply not be enough regardless of the other factors. Wildflowers is more in your general area so I'd definitely listen to what she says.

Looking at your containers they look to be about 2-feet in diameter...is that about right? Roughly, 2 gallons would put one inch of water down on the soil. You can do multiples of that to increase the watering amount. But, you need to get the soil good and moist to begin with...so if you haven't already done so, give it a good soaking.

Something else, those black containers are gonna get mighty hot. A coat of white paint might help matters. Or if you have a rigid but bendable "something" that you could wrap around the containers that could create a shade for the containers. Just sayin'...

@NewGardener95 it looks like Ed answered your question very thoroughly. I don't really have anything to add... except when I water my containers, I do so in the morning (before the sun is up too high) and typically water until it starts to drain from the bottom. That way I know it has gone all the way down to all the roots.

@intheswamp thanks for the input!

Good advice but if I can add. If your plants look like this in the evening wait till morning and see if they perked up. If they are still wilted then water as Christine suggested. Some times these type of large leaves will wilt during the heat of day and recover when it cools.