Dairy cattle are homeotherms and invest significant energy to maintain a core body temperature within a normal physiological range. Genetic changes during the past two decades have increased the average daily milk production of dairy cows. The increased production is associated with an increased level of metabolic heat load. Thus, cows have become more sensitive to ambient conditions. The environmental conditions within the housing systems of dairy cows is affected by the daily weather and the changes in weather over the course of several days. This paper will draw on research completed in the Brody Environmental Center climatic chambers as well as research conducted on commercial dairy farms. The projects have allowed us to describe important relationships between environmental conditions (including cooling systems management) and thermal balance of high producing dairy cows.