Why boaters carry a current atlas
In these waters the current often matters more than the wind. For fifty years the answer has been the Canadian Hydrographic Service's Current Atlas: Juan de Fuca Strait to Strait of Georgia — 43 chart pages of arrows, paired with an annual lookup table (Waggoner, Murray's, Washburne's) that tells you which page is "now." It works. We've sailed with it too.
But the atlas pages were computed decades ago from tide harmonics alone: no wind, no river freshet, no weather — and only 43 snapshots. Current Charts starts from a different place: NOAA's operational Salish Sea ocean model, re-simulated four times a day with live conditions, distilled twice a day into compact offline packs, and anchored to the official current stations boaters already trust.
What you get
The water, moving
An animated forecast field for any minute you pick — not the nearest of 43 pages. Scrub two days ahead; watch floods build and slacks open.
Offline where it counts
Top up at the dock (under 15 MB per region per update), then everything works with zero signal in the islands. Honest staleness warnings when data ages out.
Station-anchored honesty
Speeds calibrated against 56 official NOAA current stations, with narrows like Cattle Pass blended toward official predictions. Predictions labeled as predictions.
Flood & ebb, boater-native
Tap anywhere: signed flood/ebb curve, slack times, "max ebb 2.4 kn at 3:40 PM," plus high/low tide marks right on the timeline. The tide-table mental model, drawn live.
Built for underway
Tap your boat: an oversized live reading — speed, set, cardinal direction — that follows you as you move. One glance from the cockpit or the cockpit of a kayak.
No ads, ever
Pay for a weekend, a season, or the year: Current Charts Pro is $4.99/week, $12.99/month, or $99.99/year with a 7-day free trial on the yearly plan. Cancel anytime in your App Store settings.
Coverage
- San Juan Islands & the eastern Strait of Juan de Fuca — forecast twice daily
- Canadian Gulf Islands — forecast twice daily
- Victoria & the Strait of Juan de Fuca — forecast twice daily
Named passes with slack and max flood and ebb include Deception Pass, Cattle Pass, Rosario Strait, Haro Strait, San Juan Channel, Boundary Pass, Lopez Pass, Thatcher Pass, Spieden Channel and Guemes Channel.
Questions boaters ask
What is a current atlas?
A book of charts showing how tidal currents flow through a region hour by hour, paired with an annual table that maps any date and time to the right chart page. Current Charts computes both halves live.
How is Current Charts different from the paper atlas or PDF chart apps?
The paper atlas and chart-viewer apps show fixed patterns computed decades ago from tide harmonics alone. Current Charts uses NOAA's SSCOFS ocean model, re-run four times daily with live weather, river flow, and sea level — then anchors speeds to official NOAA current stations. A full moving field for any minute, not one of 43 fixed pages.
How accurate is it?
The model captures what fixed harmonic charts can't — weather, river flow, seasonal variation — and we anchor its speeds to 56 official NOAA current stations, blending the narrows toward official predictions. It is still a prediction, and we say so on every screen.
Does it really work offline?
Yes. Offline-first is the architecture, not a feature: packs live on your phone, and the app renders everything locally. The only thing that needs signal is topping up tomorrow's forecast.
iPhone? iPad? Android?
iPhone and iPad today, with the same chart filling the larger iPad screen. Android interest? Tell us.
Can I navigate with it?
Use it to plan — never as your only source. Current Charts shows model predictions, not measurements, so wind and weather can change what you find. Always compare with official charts and publications, and use your own judgment, for navigation decisions.
Plan your next crossing
Download on the App Store$4.99/week, $12.99/month, or $99.99/year with a 7-day free trial on the yearly plan.