Day 4: Date
I imagine that sunset would be a good time for Zuko and Katara (both the sun and moon would be out then) and that Katara would know the best spot to see it from.
I just want to say that this was the picture my computer did not want me to post. I don't have a battery in my laptop bc it was bad and the dang thing came unplugged about 87 times, making me lose everything that I hadn't saved. D: I won in the end though.