Our sensor nodes log depth, temperature, and light every fifteen minutes, all winter. Plotted end to end, a season of cold water reads like a slow heartbeat.

Cold, then a spike

The line sits at 4 °C through January, climbs gently to 8 °C by April, then jumps. The jump is the signal — a few warm days, and the blades are done growing. The calendar never sees it coming, but the telemetry does.

Why we publish it

A season of data is more useful shared than filed. Researchers pull the feed, farmers compare notes, and anyone can watch the water warm in real time.