After reading the information in this http://corn.osu.edu/newsletters/2012/21-22/high-temperature-effects-on-corn-and-soybean  under the heading How do high nighttime temperatures affect corn and soybean production?, i put the following table together from some recent air temperatures that i recorded.

(douglas night time average air temps starting 8 10 2015.bmp)

douglas night time average air temps starting 8 10 2015.bmp (2516KB - 82 downloads)