A line chart displays temperature readings over a week-long period, with each hour marked as a point along a smooth, naturally curved line. Data about San Francisco temperatures is loaded from a CSV file using D3's `csv` utility. React manages the asynchronous data loading via hooks, while D3's `scaleTime` and `scaleLinear` map the timestamp and temperature values to SVG coordinates. The chart renders axes, labels, and the data line with circles as SVG elements, using `d3.line` with `curveNatural` for the path and `d3.timeFormat` for the weekday tick labels.