Alabama has warm summers, with the 20 year maximum day mean temperature at several research stations reaching around 90 °F during the months of July and August. Soybean as a summer crop is well adapted to grow in these environments without showing symptoms of temperature stress or yield penalties (Salem et al., 2007; Djanaguiraman et al., 2013). However, due to the high humidity, night temperatures are elevated, with several research stations reaching minimum mean temperatures (MMT) above 70 °F for at least 20 days each month in summer, and with some summer having months with at least 8 days with a MMT of 75 °F or above. In previous research, it has been shown that high night temperatures...