There are twenty four hours in a day. Do you know when your most productive writing time is during that twenty four hours? You may be a morning person but that doesn't mean your most productive writing time is during the morning...same goes a for night owls. Or it might.
You need to experiment with various times during the day to find your prime time to be creative. Mine runs from about 10AM through 4:30PM. As you know I hold down a full time 9-5 job so the only time I get to write during my Prime Time is on the weekends. Does that mean I don't write during the late afternoon? Evenings? No, it just means it's a little harder for me to get my creative juices going. Sometimes I jot down notes about my WIP or a new idea to help prime my creative juices well when I'm not writing during my Prime writing Time.
When is your Prime Time to write?