This visualization displays yearly temperatures for February and March across U.S. regions, with each line representing a groundhog shadow category (full shadow, no shadow, or partial shadow) from 1895 onward. The data comes from Data Canvas - Sense Your City. Using d3.csv and d3.nest, the code groups records by shadow status and renders them as smoothed line paths with d3.line and curveBasis. A d3.scaleOrdinal with schemeCategory10 provides color encoding, accompanied by a custom colorLegend module, while axes are generated using d3.axisBottom and d3.axisLeft.