When I first started writing, I would write late at night and into the wee hours of the morning with my cat curled up at my feet. During those years I found I did my best creative thinking at that time of day. Daytime was filled with other activities outdoors.
Now, I can't do that. Instead, I'm happily in bed hugging my pillow.
My best writing time is first thing in the morning. That's when the old brain is the sharpest. By noon, that's it, my creative juices have stopped flowing. After a good lunch, I either nap (have learned to love those), do a little house cleaning, or I spend the rest of the day reading other people's work.
What time of day is the most productive for you?
On a side note, just finished Real Mermaids Don't Hold Their Breath. It did not disappoint and there's another sequel waiting to be written, I hope.