The southeastern United States, characterized by humid subtropical climate, experiences extended periods of high ambient temperature and humidity, which pose significant challenges to dairy cattle. Heat stress in this region is chronic and often severe, leading to decreased dry matter intake (DMI) and milk yield. The combination of high ambient temperature and humidity impairs the cow's ability to dissipate heat, causing a rise in body temperature and a decline in productivity. Management strategies to mitigate heat stress include physical modifications such as shading and barn design, as well as the use of fans and sprinklers for evaporative cooling. Genetic selection for heat tolerance and improved nutritional management are also crucial. The effects of heat stress on cow performance are mediated through changes in body temperature, DMI, and milk yield, with critical thresholds for temperature-humidity index (THI) identified. Evaporative cooling systems, such as tunnel ventilation and high-pressure mist, are being investigated to enhance cooling capabilities. Additionally, the impact of heat stress on dry cows and heifers is discussed, highlighting the need for targeted interventions to maintain productivity and calf health.The southeastern United States, characterized by humid subtropical climate, experiences extended periods of high ambient temperature and humidity, which pose significant challenges to dairy cattle. Heat stress in this region is chronic and often severe, leading to decreased dry matter intake (DMI) and milk yield. The combination of high ambient temperature and humidity impairs the cow's ability to dissipate heat, causing a rise in body temperature and a decline in productivity. Management strategies to mitigate heat stress include physical modifications such as shading and barn design, as well as the use of fans and sprinklers for evaporative cooling. Genetic selection for heat tolerance and improved nutritional management are also crucial. The effects of heat stress on cow performance are mediated through changes in body temperature, DMI, and milk yield, with critical thresholds for temperature-humidity index (THI) identified. Evaporative cooling systems, such as tunnel ventilation and high-pressure mist, are being investigated to enhance cooling capabilities. Additionally, the impact of heat stress on dry cows and heifers is discussed, highlighting the need for targeted interventions to maintain productivity and calf health.