We will be staying at a rental property in Port-en-Bessin for a week beginning July 4. After doing some D-Day site touring, we will take one of our remaining days to make a day trip to the Mont. I've downloaded the tide tables for this year, and it seems that the tide coefficient on our possible days will be 80, 74, and 66 for the morning high tides on Wednesday, Thursday, and Friday, respectively, and 77, 70 and 61 for the evening high tides on those same dates. In point of fact, unless I can persuade my fellow travellers to make an early start, we probably are likely to be there during a low tide, but in deciding whether I need to lobby for that early start, I need to know if it would actually be worth it. I've been led to believe that if the coefficient is low enough, one doesn't see any water in the bay around the mont even at high tide. Is that correct? If so, what level of coefficient do we need to see water in the bay.

If we aren't going to see any water in the bay regardless of what time of day we travel, that would probably push us toward a late afternoon or evening visit (possibly trying to arrive after most day trippers have left, as we can stay as late as we like).

I'm also interested in information about the evening visits to the Abbey which I understand they have during the summer time, and would like opinions on whether that is worthwhile--would you time your trip so that you actually see the mont in the evening, hopefully after most people have left, if that's an option?

There will always be a bit of water since there are some small rivers that drain into the bay. But it's true that when the tide is at its lowest, it is basically just one huge mud flat. Even then it is always interesting to see the tourist groups that insist on walking to the Mont with a guide (must too dangerous without a guide -- quicksand, etc.)

I have never worried about my arrival time, because the tide is different when you leave 2 or 4 hours later. So you might arrive with a full bay and then see it empty later, or the opposite. Watching the tide coming in is amazing. While I would not say that the tide comes in as fast as the proverbial galloping horse, it is fascinating to see how each little wave comes in farther than the previous one and does not recede.

Coefficient... Please help me, never come across this term before

I'm guessing the OP meant confidence and the "smart" device auto"corrected" it to coefficient (which is a mathematical term).

We were there in 2011 and in 2004 and took these pics. The first 3 were in 2011, the last one in 2004. Even at low tide it is interesting.

I admit that I don't understand the reference to the "coefficients."

I can say that I watched the tide come in there once, starting when all I could see for as far as I could see was a vast mud flat with a few ridges and streamlets and some guided tour groups until helicopters forced them to land. It seemed that nothing happened for an absolute age, and then, finally, I could see water in the distance, growing closer and closer ever so slightly. And then, looking a bit to my right, I saw the proverbial galloping horse as the water broke over an obstacle in an area whether it seemed that NOTHING had been happening. Suddenly, water rushed in and around, filling the area in a surprisingly short period -- and almost no one around me knew what had happened, as they hadn't been looking in that direction. (I heard them saying how disappointing it was.) So bizarre! So awesome! I'm glad I saw it, even though I spent a very long time watching basically nothing until then. (I had positioned myself at a parapet wall well in advance just to make sure I had a good spot.)

Don't know if that helps at all, but I hope it does!

Tides are indeed measured by coefficients.

As kerouac notes, if you download the chart from the official site (link here) you will see that they have a "coefficient" listed for each tide, which gives some indication of the height of the tide. It's useful in comparing days. I found out from another site that the days in orange on the chart are days when the water makes it up to the bay around the mont (on other days, it's just a mud flat all day).

The point being that, if the tide is going to put on a real dramatic show at high tide, it makes more sense to time your visit to the tide. Otherwise, any time of day might do, all other things being equal.