How to temporarily secure glass doors to backyard?

A wooden dowel of adequate length wedged into the door at a sufficient height should do the trick.

@kritiper I’ve used a wooden dowel for a sliding glass door. But having a hard time envisioning how this would work on doors that open outward?

You’ll have to wedge it into the handles so the dowel goes from jamb to jamb horizontally.

Or tie it in place with a piece of rope.

I would just go with a chain and lock for now and call them in the morning and let them know you need the door to lock for the childrens safety. If its a matter that the lock works but doesn’t align with the socket part then try lifting the door a little before engaging the lock.Doors will swell or sag and so it won’t fit right sometimes.
If it isn’t any of those things and you just feel the lock would be easy for the kids to open because they can easily turn the lock to open it then use a zip tie.

Can you twist a metal coat hanger through the handles? You can bend it to make it really tight by using a piece of flatware as a tourniquet handle.

Can you use a strong rubber band (the type used for luggage on bikes) or very strong tape to connect the handles to each other, making it impossible to turn either one? I guess this would only work if you don’t need to use the door at all.

Alternatively, maybe push something heavy in front of the door from the outside.

Pictures might help us provide better suggestions!

Thanks for all of the suggestions, guys. Appreciate the brain storming!

We figured out that you have to lift the lever in order to activate the locking mechanism.

It was just odd that the metal bolt didn’t move in and out when you clicked the manual lock.

@raum Hope you’re somewhere nice and doing something fun!

Thanks! We are in Orange County visiting family. I’m not the biggest fan of Orange County. But so good to see family—especially after this pandemic. :)