I would especially like to know if there are primary sources explaining the climate of major southern cities such as Atlanta or New Orleans to Western Europeans prior to their immigrations.
Hey there, check out these past threads while you're waiting for a more specific answer:
How did laborers in the American South "beat the heat" before the invention of air conditioning? by u/Georgy_K_Zhukov
How did air conditioning change the culture of the southern United States? by u/svarogteuse