Greenhouses have to be designed to not only capture solar technology but also adequately ventilate excess heat if temps get too hot.
You should always make sure you have sufficient vents in the roof of your greenhouse as heat rises and you want that heat to escape.
Greenhouse roof vents work really well because they are located where heat gathers naturally at the peak of the roof.
If vents in the roof are not possible, make sure to at least have a window to two you may open.
Ideally you need to have cross ventilation so two windows upon two sides of the greenhouse work greatest.
However you should not leave the vents or windows open at nighttime as you’ll lose any kind of heat gain and cool your greenhouse an excessive amount of.
And that means you close the vents or windows at night and what happens another morning: you forget! Right now your greenhouse overheats and if you’re unlucky, you lose some plants.
Or you forget to close the vents at nighttime as well as your vegetation suffer if the night time is too cool.