How can you tell if a hive is about to swarm or too hot?

Perform an inspection for capped swarm cells. It is not uncommon to see uncapped queen cell this don’t necessarily mean they are on the verge of swarming. With strong populations during hot weather many bees will hang outside the box to help control temperature in the hive. Like when I was a kid during hot weather mother would kick us out of the house to cool it off.
If you find a lot of capped swarm cells swarm prevention is in order, splitting is the best way to head off a swarm. You can always recombine later in the season when the swarm season is over.

Depends on a bunch of things.

Is the brood box packed with nector or is there room for her majesty to lay?

Queen Cups are common and lots of colonies have them, this is healthy

Queen cells on the other hand are another issue....look up into them and see if there is a pile of royal jelly in there, if there is, thats a sign of prep to either swarm or to supercede depending on whether the cell is in the middle of a frame or the bottom.

Heat or crowding or both can contribute to bearding. Bearding does not mean that they are, or are not about to swarm. But if the weather isn't hot, I'd investigate further.

http://www.bushfarms.com/beesfaqs.htm#bearding

Yea its pretty hot already in Louisiana, and until they came outside they didnt have much shade, I've solved that problem. But your right they hang on each other like a beard in the front and come out of every crack and crevis so I'm thinking hot but I don't want to be too late and find out there gone, Thanks

what is the difference between a queen cup and a queen cell? I think I know what a queen cell looks like.

a queen cup is about 1/4 to 1/2 inch deep. and looks like a the cap on an acorn. a queen cell is about an inch long, and capped over on the bottom. usually has dimples like on the shell of a peanut, and hangs down from where it is attached on the comb.

I see the term 'Swarm Cells". Is that a queen cell or what and where are the swarm cells uselly located? Newbe here...lol

Most of the time swarm cells are located on the bottom bar of a frame but not always and no matter where they are located on the frame they are still queen cells.

Thank you Honeyman!!!

If your population is booming, have you added enough space? Enough supers? Being in LA you might also want to consider a screened bottom board, both for pest management, and ventilation.