Most people weigh more at night than morning. If you weigh less at night, it usually means dehydration. Make sure your getting enough water to flush out sodium and keep things moving. You should pick one time of day to weigh, in order to accurately gauge your weight loss. Same scale, same time, same clothes! Which ever time you decide, keep it consistent. I like morning before eating or drinking anything and after going to the bathroom. Keep in mind many other factors affect the scale such as sodium in foods you eat, all the food you eat and drink all day, exercise, medications, sickness, stress, lack of sleep, etc. Our water weight fluctuates all day long.