I have discovered that I like quiet in the morning. Like the sound of birds singing, sprinklers going, trains about a mile away, newspaper pages turning... and not much else. A cup of coffee is nice.
An article in CNN says that the best time to exercise for fitness is the early afternoon. A web page at Columbia University says exercise whenever you feel like it. Morning workouts get you going and improve your mood. Afternoon workouts relieve stress and are more productive for muscle tone. I guess that means I should swim in the morning, but do physical therapy for my shoulder in the afternoon. Okey dokey.
I have to plug In Motion Fitness in Chico, CA. They are open 24 hours a day during the week and open at 5:30 weekend mornings. Very early in the morning I have the pool to myself most days. They keep the pool heated 12 months a year, rain or shine, and when the clock is working (about 60% of the time) you can even time your laps. Perfect.