Fetch started with a simple frustration — lying in bed at 6am, checking three different weather apps, still not knowing whether Morse would be glass or choppy by the time we launched the boat.
Wind speed alone doesn't tell you where good water is. A 12 mph northwest wind on Morse creates very different conditions in a protected south-facing cove versus the open main channel. No app was showing that.
So we built one that does.
01
Fetch geometry — We calculate the wind travel distance across open water for 569 points on each lake. Longer fetch means more wave buildup. Shorter fetch means more protection.
02
Live wind — Every request pulls current wind speed and direction from Open-Meteo. We calculate which direction the wind is actually coming from and apply the right fetch values.
03
Depth data — USGS 2016 multibeam sonar bathymetry. Shallow water gets choppy faster and stays rough longer. We factor this in so you know where the deep clean water is.
04
Lake score — A fetch-weighted 1–10 score tells you whether to go out at all. Then the heatmap shows you exactly where to go if you do.