What is the minimum number of floors you need to be up, where you can leave the window open at night without having to fear someone climbing in through the window?

It depends so much on where you live. I live in a safe neighborhood near a small city that has more crime. I can leave my second story window open all night and have a ground floor clerestory window that is open too. if I lived within the city, I might be reluctant to leave windows open at night unless I were on the thrid or fourth floor.

Some climbers go up skyscrapers without ropes, so in theory, almost no height is safe.

Eh, if I’m on the second floor or higher, I have no problem leaving the window open. As long as there’s no balcony or deck outside that window.

Depends on how much crime you have in the area. And how accessible your window is. (ie next to a stairwell, balcony, etc.)

Safe blue-collar neighborhood, loud, large, dog. Anything could be open.

@ragingloli NOT an irrational fear!

Same as @Canid. Cato would eat anyone who broke in.

If anyone has heard my talks about home security, no windows are 100%.
Criminals, are opportunists.
A visibly open window, is an opportunity.

You could install bars, on a certain window, and leave that one open.

It must be nice, living in a colder climate. If I left a window open, I could have a zoo in my house.

I used to leave my second floor windows open, in my old apartment (in a pretty rough neighborhood.)
It would have taken a ladder to get to it.
Of course, I was 6’5 300 lbs. I always had my shotgun in whatever room I was in, and had a pitbull…

@Dutchess_III Pretty sure Rocky wouldn’t eat anybody, but in this neighborhood he is the leader of a very vocal canine choir. We had some sort of wildlife brawl going on at 3 AM Monday night, lights on in every house, every dog barking, it took about an hour for all to settle.

I doubt those critters will be back!

To be absolutely sure, four. I have two stories and sleep upstairs. If someone really wanted to get up to my windows they might be able to. The third level would be the attic which is accessible to a small person by removing the metal soffit that’s the eave for the second floor.. The fourth level would be on top of the roof and, again, a very in-shape teenage boy could do that. I’ve seen them climb up to my second and third floor balconies in the house I where I used to live. I live in a very nice area and everyone other than me has security systems with cameras all over the place. I believe anyone who came near my house would show up on someone’s system. So I have free security surveillance.

With no level surface access to the window, 3rd floor.
With a deck or balcony, 4th floor.

This is one of few complaints I have about living near the city center on a busy road. We are on the first floor, though the exposed basement adds several feet from the ground to our windows. You would need a ladder to get to our windows. I still don’t feel safe leaving the windows open at night.

This so much depends on where you are and what the structure is like.

For some reason my mind went to “Rapunzel, Rapunzel, let down your hair, so that I may climb thy golden stair.!”

It really just depends on what you feel is reasonably safe as compared to what is technically possible. I live on the second floor of an apartment building and I have no problem with having my windows open all night, although I tend to shut my balcony door. But I do know that I would never rent a ground floor apartment for similar reasons.

As others have said, it would all depend.

Where I live, I feel 100% safe at all hours of the day and the night. I have taken walks in the middle of the night and not seen one person walking or in cars. I live in an enclave where it’s all neighbors and outsiders are very obvious. I lock my door at night but if someone wanted to, they could climb in another way. I feel if a criminal is determined, they’ll get in.