plants become limp from dryness, excessive heat, too much water (waterlogging), diseases, high salts in soil (from fertilizer), etc.
You did move them out into the night which should have perked them up if the reason is due to "excessive heat". It's possible that the
plants may have been extremely heated up and may take a few days to perk up.
And you said you watered them, which should rule out the possiblility of "dryness". Are they getting better over the watering? If not, check the next reason.
How often do you water? Too much water, pots with no holes, and/or saturated soil can lead to root rot. Check the soil. Does the soil feel soggy and wet? Rotten roots are brown and mushy.
Let's try to find the reason for the wilting before you do anything to the
plants.
Good luck! Hope they perk up
!