New Orleans has a hellish climate. Indianapolis by far.
Just FTR, I've spent my last two summers in DC and its about the same as New Orleans.
The data doesn't really bear this out. Summer is both longer and hotter in New Orleans. There are two months of the year when the average high is above 90 in New Orleans. There are zero in Washington. There are six months of the year when the average high is above 80 in New Orleans. There are three in Washington. New Orleans is also substantially more humid.