From what I understand, the June 1944 landing at Normandy was kind of an "iffy" thing, because of the weather. That's because there were only a few windows of opportunity each year, when the tides were properly aligned, and then only if the "atmosphere" cooperated. If the invasion hadn't taken place on June 6, there was only one more theoretical opportunity in July, 1944, one that wouldn't have materialized, because of the "air." Without the June 6th invasion, the invasion would have to have been postponed until 1945.
Did the Germans face similar tide and weather issues with their "Sea Lion" plans for the invasion of England? On one hand, they had a wider choice of landing sites than the western end of the English Channel, but on the other hand, their landing craft was far less sturdy. Was it a situation where the Germans would not only have had to win the (air) "Battle of Britain," but have control of British skies on a few critical days that mattered because most others did not?