This map of plant hardiness zones displays the average annual extreme minimum temperature from 1976–2005 across the contiguous United States, using a divergent blue-to-red color scale. It renders the topojson data via Canvas, with d3.geo.path drawing each polygon and the context’s fillStyle applying the temperature-based color. A separate SVG overlay provides a color legend with a d3.svg.axis and tick marks. The zones are sorted by temperature and drawn in order, with data sourced from Bill Morris’ Open Plant Hardiness Zones project.