Dear Vicki, My greenhouse even with exhaust fans easily does get to 90 to 100 on sunny days. But on overcast foggy days which we can have in summer it is cooler. But the temperatures can easily drop to the 50ties at night. I hadn't thought of the night time temperatures, but it is true we can't grow some of the things that do well in coastal Southern California and I think the night time temperatures are a factor. Just another reason perhaps to send them on their way. Mary Sue