Last night our cat who is only about 7 months old went out for a wander at 7pm and didn't come home until 11.30pm - I was calling her, shaking her biscuits etc every few minutes but she must have gone right off a long way away. We don't have a cat flap and I really needed to go to bed but couldn't until she was home - it must be what is it like having a teenager! Our old cat used to sleep outside at night in the summer but only when it was warmer than this but is it ok to leave a young cat out overnight when weather is nice? If not I can see some late nights for me this summer waiting for her to return