Go-Day Forecast weighs wind, waves, current, water temperature and weather along a chosen swim route, hour by hour.
How to use it
The app follows the order you plan a swim in: draw the route, find a week, choose the day, then look at it hour by hour.
- Draw a route: Tap the map to drop waypoints. Tap the route line to add a point in between; drag a waypoint to move it; tap it to delete it.
- Start Date & Time and your Target Speed: Adjust these and the app works out the distance and how long the swim will take.
- Set a Start Date & Time or Go-Day will show you options.
- Having a Target Speed set will help give a more accurate forecast.
- Swim Window: Based on the route you create on the map, find the best week for a swim. Swim Window ranks the weeks of the season against ten years of water data. Click a week to see it year by year.
- Route Forecast: Once in your swim window, see the conditions along your swim, hour by hour. Route Forecast shows what the models predict along your route for your start time. The route is divided into points, one per hour of the swim, each placed where you will be at that hour.
- Go-Day: Let the app show you options. Go-Day scores a start time for every hour of every day in the next five days. Then gives you a primary and secondary option for day, time, and the direction to swim.
Why we built it
This app pulls the water conditions information into one place. A swimmer needs to know what will it be like where I will be, when I will be there, for every hour from the first stroke to the finish.
The information you need is out there, but it is scattered: a water model from one agency, wind and waves from another, buoy readings from a third, warnings somewhere else. Each one answers a question about a single spot on the lake at a single moment.
Go-Day Forecast puts those sources together along your route, at your pace. It does not invent conditions. When a forecast is not available for part of the swim, that part is left blank rather than filled in.
This app does not use AI, it uses the forecast data sources listed below.
Where the data comes from
- Water temperature and current come from NOAA’s Lake Superior Operational Forecast System (LSOFS), which covers the whole lake and runs five days ahead.
- Wind, waves, sky, air temperature and storm risk come from the US National Weather Service in US waters and from Environment and Climate Change Canada in Canadian waters.
- Live observations come from GLOS Seagull buoys around the lake.
- Marine warnings and beach hazard statements are issued by the US National Weather Service and cover US waters and shores only.
- The Swim Window history is drawn from NOAA GLERL’s Lake Superior FVCOM reanalysis of surface water temperatures from 2013 to 2022.
This site and app use Google Analytics to track usage data to help diagnose errors and develop the site and app.