My official weigh day is Sunday Morning after going potty and before my bath just after I wake up. I weigh naked and also try not to drink many fluids at least 3 hours before weighing. I have a habit of drinking water all night. Sometimes I will get an urge to weigh in, in the middle of the week so I do just to see how it is going, but always just after I get up after a potty break and before breakfast. If I'm lower I update my stats and if my weight is higher I let them be because I know in a few days it will go back down.