We don't often sleep with the windows open because it's usually either uncomfortably cold or hot, but there are periods in the spring and fall when we can. Recently an owl's hoots woke me in the middle of the night. We've heard owls here before, sometimes as we were just getting to bed, and it's always a nice sound with a distinctive rhythm. From what I just heard on YouTube, I'd say it was a great horned owl.
The next few nights I've hoped for a repeat performance and have been a little disappointed not to hear it. Maybe tonight.