Tide times
Tidal streams
Flood tide flows clockwise around Ynys Môn and ebb flows anticlockwise. The Straits are a special case, but are well documented in the Menai Strait sailing almanac.
The flood fills the Straits from the Abermenai end. It briefly flows eastward throughout the whole Strait before being met by the progressively strengthening flood entering from the Penmon end. This creates a section of slack water where the tides meet, moving westwards until it reaches its westmost position at the Swellies between two and one hours before local high water.
The Straits continue to fill until local high water, then start to empty, first from Abermenai and then from Penmon. After a brief time when the whole flow is westwards, slack water moves westwards down the Straits from Penmon, reaching Caernarfon about five hours after high water. The cycle then repeats.
