I think as long as you weigh yourself at the same time everyday (or every week, month, whatever) you'll start to see some consistency. You will weigh about a kilo more (2.2 pounds) in the evening versus in the morning; you'll also weigh more after a workout as your muscles retain water.
You'll find a lot of discussion on these boards about how often you should weigh yourself; everyone seems to be different! Personally, I only weigh once a week. Others enjoy weighing everyday to get to know their body's fluctuations. And it seems the medical community goes back and forth on which is the best for weight loss: everyday or every week? Just find what you're comfortable with and don't worry about day-to-day fluctuations, if that's the route you choose to go: they're normal!