swim night or day?

i usually swam evenings to start with,then increased to 3 evenings per week.I tried today(because i work mon to fri,and today is sat)swimming in the morning.I got up at 6 and got to the pool for 7am,i really enjoyed it the only thing was i didn't feel as flexible in the water as i do evenings after work,i tried stretching but still not much improvement..will this improve with more morning workouts or should i stick to nights?