@ossobuco,
When the weather here gets warm, and my dog is in the backyard, I keep a filled water dish out there so she can drink and cool down whenever she needs to. If you're concerned about Katy getting enough water when she's out, perhaps you should leave a dish of water out there with her.
I used to use a bell to signal one of my dogs to come from wherever she was, and it worked like a charm. In fact, it generally worked much better than calling her, particularly when she was older, perhaps because it was easier for her to hear the bell.
That same dog not only hated the wind, when she moved from puppy-hood to adulthood, she flatly refused to go out in the rain. If I took her out in the rain, she immediately turned around and pulled non-stop to go back in the house. The solution, in her case, was to buy her a raincoat. Even though the only one I could find at the time lacked a hood, just covering her body made her willing to walk in the rain. She let me know what she wanted.
It sounds like you and Katy are learning to communicate well. As long as she does signal you that she needs or wants to go out, it doesn't really matter how she does it, as long as you recognize it as a signal. Whichever signal you respond to, by letting her out, is the one she's going to repeat.
What does she want at 3:45 am? Does she need to go out then?
I'm loving this thread. I'm so glad the two of you found each other.