This choropleth map visualizes average annual temperatures for U.S. states, using a red-to-blue sequential color scale to encode hotter and colder climates. Built with D3.js v7, the visualization renders SVG paths from TopoJSON data loaded via the `topojson-client` library, projecting states with `d3.geoAlbersUsa()` and `d3.geoPath()`. Hovering over a state triggers a tooltip that displays the state name and temperature value, with the map including a color legend. The underlying temperature data is stored in a JavaScript dictionary.