Yes. There is some evidence in the bible that Jesus, and his disciples, often prayed in the morning hours. However, there is no specific commandment in the bible to do so. It is probably good to pray at the start of any day to ask God's guidance but it is also a good idea to pray when you are at your best, during the times you are most creative. It is vital, however, that we have a consistent and active prayer life. Emphasis should be placed on the world LIFE. When we have a prayer life, the spirit of prayer pervades all the hours of the day.