I used to live in New Orleans and I grew them during the winter there. When it gets hot, they will die. As pots go, it's always good to go with the biggest one you can accomodate. I rarely buy one less than l4 inches in diameter. Twenty 24 inches is my favorite. With a big pot, there's plenty of root room and you don't have to water as often. If your pot is less than 7 inches in diameter, it would be wise to put your plants into something bigger. And, perhaps you can put your sweet peas in a spot where they get afternoon shade? With a little luck, you could have some flowers before hot weather. If you have seed left, put them in a ziploc bag and store them in the fridge for next year.

I agree with Donna on all counts. Sweetpeas do NOT like the heat and are best grown in the late winter in your area.

Do the most you can to keep the roots as cool as possible...largest pot you can use, pot should be white or other light color, try to shade the base of the plants, perhaps some kind of mulch that might keep sun from heating the soil so much. This last is said facetiously, but perhaps it's not as silly as I first thought...water with ice cubes.

Keep picking the flowers or pinch off the dying flowers or they will stop producing blooms.