Reader A.L. reported:
"I was taught while in college studying for a crop science degree that the rule of 100 applies to storing seed. Subtract the percent humidity from 100 and you will have the highest temperature seed should be stored at that humidity.
If the humidity of a storage facility is 20%, then seed can be stored there at up to 80 degrees F. If the humidity is 60% then the seed should be stored at 40 degrees F."