About tide & current data
This page describes where we get our currents and tide data.
Use with caution. Harmonic predictions are a rough guide — they do not account for wind or waves, which may push slack earlier or later. These predictions are for nearby reference stations at specific depths- not the actual dive site! Harmonics may be periodically updated by NOAA, meaning timing offsets to a specific dive site may change. Dive within your limits, note the real conditions when you arrive. Always have a more experienced diver show you the site in person your first time at a site.
US tide and current predictions
From NOAA CO-OPS
We also offer Xtide predictions for some locations in the US. Read about such usage in the BC section below.
BC tide and currents predictions
We use XTide current predictions using David Flater's and other harmonics packages. When doing so, chart rows link to Dairiki or arthroinfo for cross-checking. Note that there are different prediction depths and harmonic packages available for xtide. When pnwdiving.com uses xtide, it uses the 2018 harmonics package which is intended to match the xtide predictions that Dairiki and arthroinfo uses.
Some Canadian harmonics in XTide are licensed for non-commercial use only. pnwdiving.com has no advertising, sponsorships, or paid features.