Slack water times at Honolulu, HI
Today's slack water at Honolulu: 1:11 AM · 6:10 AM · 1:48 PM · 9:08 PM
Next slack: 1:11 AM
Today in detail
Flood is the incoming current, ebb the outgoing. The strongest flow falls between two slacks.
7-day slack water forecast
Computed from NOAA harmonic constituents. Datum: MLLW. Predictions are estimates for reference only, not for navigation or life-safety decisions.
How accurate is this?
These are the tide turns at Honolulu, computed on this page from NOAA harmonic constituents. Slack water lands on the tide turn where the tide behaves as a standing wave, which is typical at the head of a bay or harbor. At an ocean inlet, in a channel joining two basins, or in a tidal river, real slack can fall well away from the turn, by up to about three hours. Where NOAA publishes a current station near you, its predictions give slack directly and are the better source.
What slack water is, how long it lasts, and why it rarely matches high tide →
Get a 30-minute warning before slack
The next slack water at Honolulu is at 1:11 AM. Slackwater puts the countdown on your wrist and your lock screen, and alerts you before the turn. It works with no signal, because the tides are computed on your iPhone.
Coming soon to the App StoreSlack water questions, answered
What time is slack tide today at Honolulu?
Slack water at Honolulu, HI today is at 1:11 AM · 6:10 AM · 1:48 PM · 9:08 PM. These are the tide turns, computed from NOAA harmonic constituents.
How long does slack water last?
It depends on how hard the current runs here, not on how high the tide is. For a roughly sinusoidal semidiurnal current, divide 120 by the peak current in knots to get the rough number of minutes under half a knot. A spot that peaks at 2 knots gives about an hour of workable slack; a 5 knot race gives about 24 minutes. True zero current is instantaneous, so any useful answer has to name a threshold.
Is slack water the same as high tide?
Often not. Slack matches high and low tide only where the tide behaves as a standing wave, which is typical at the head of a bay or harbor. At an ocean entrance slack falls nearer mid-tide, roughly three hours off the printed high, and in a channel between two basins it arrives when the levels at each end are equal.
Where do these times come from?
They are the turning points of the tide curve, computed from NOAA harmonic constituents, the same method NOAA uses for its published tables. They are an estimate of slack from tide height, not a measured current prediction.