I usually choose first thing in the morning. However, if that's not convenient for you - then just be consistent, and always do it at around the same time of the day, weekly
Fitness Minutes: (86,286)
11/13/12 7:27 A
Another vote for first thing in the morning. Your weight will fluctuate more during the day as you eat and drink. I find I get a pretty predictable weigh-in result first thing in the morning before I eat or drink anything.