The maritime tropical air mass is the warm humidity often felt in the air in the southeastern part of the United States. It is the result of the combination of direct sunshine, the Gulf Stream and the Gulf of Mexico.
The area experiences a large amount of water in the air due to evaporation of the warm waters of the Gulf of Mexico and an abundance of strong sunlight. The warm, moist air conducts heat to the lower levels of the atmosphere, making the region's typical temperatures higher than other parts of the country. Inside of the maritime tropical air mass, it is more likely for thunderstorms to form and for the air to have a high dew point.