Lots of Charolais down in deep south Texas that seem to do just fine. But around the Houston area, just anecdotally speaking, it seems like they fall apart a bit more than they do out in the Texas hill country, possibly due to the combination of heat, humidity and lack of night time cooling. Also our grasses are a lot weaker than hill country grass, and possibly S. Texas grass also. But I'd guess that if Charolais can thrive in the hill country and in deep south Texas they can probably handle anything the southeast of the USA can throw at them. Plenty of Simmental around me near Houston and they seem to do pretty well also. Don't know why, but we see relatively few Gelbvieh in these parts.