I have just purchased several fall window gel clings. Hung them on my screendoor.

Problem is that they keep falling off at different times of the day and night.

Is it because they get to cold during the nite (only in low 40's) and lose the ablitiy to cling or just bad clings. Is there anything I can to do to enchance the cling

You could try to moisten them with plain water. But, if you're trying to stick them to the screen itself, I don't think that'll work too well.

They have to be on clean glass. I use alcohol to clean the window or mirror before placing the clings.

Also, repositional glue might help.

They only cling to glass. There are different brands available. My Gel Gems are much stronger than other less expensive brands. However all of them will be affected by the sun, so if they stay up for several months, they will fade. Right now I have some fall leaves up as well as some halloween ones. Occasionally the Gel Gem website offers some for free.