For me any water retention happens during the latter part of the week (2-3 days) before my cycle starts. It normally comes off during TOM which can be attributed, in my case, to increased *ahem* bowel movements LOL
I get a pound and a half about five days before my cycle hits. And another pound and a half around CD1 (possibly a day before, possibly a day after). And about three pounds for ovulation. The weight tends to stick around for 4-6 days, then come off and I go back to weight loss as normal.
I mark my graphs with when I ovulate and start my cycle, so that I can look at them and say "See, it happens every time!"
Either the day before TOM shows up or the day of, I gain about 2lbs or so. If I don't gain any then that's normally an amazing sign. It usually goes away right be the end of TOM (or maybe one day beforehand). Then I tend to stagnate until after I'm done ovulating (although I've sometimes had loses in between TOM and ovulation ).
I start gaining 4-5 days before and it doesn't go down fully until about a week later. It is really pointless for me to weight at all during this time period - even though I know it happens, it still magically effects my mood and makes me a debbie downer.
My biggest weight gain due to fluid retention happens at ovulation time. I tend to gain 4-5 pounds and hold it for at least a week. Fingers like sausages, heavy feeling... Sucks every time. I only gain maybe 1-2 for the start of my cycle, and it only sticks around for a few days.
I gain 1-2lbs the day before my time is due to come and start feeling my stomach get all bloaty and distended feeling. On the first day I gain another 2-3lbs and this last till about the 3rd day and then slowly starts coming off bit by tiny little bit. It probably takes a good week to get off completely. I know it happens every month but I am always shocked and discouraged by the numbers on the scale. I also tend to feel heavy and sluggish and just not good!
I gain 2-4 pounds a day before TTOM and it starts to come off about day 3 of TTOM. I then start to gain 2 days before ovulation 3-5 lbs and then for 10 days I'll drop most of the weight for the month during that time. Anywhere from 7-10 pounds depending on how good I've been with food and exercise.