This multi-line chart displays daily temperature variations across several cities, with each city represented by a colored line and identified through a legend. The visualization uses D3.js v7 to load CSV data from a remote GitHub gist, parse dates with `d3.csv` and `d3.autoType`, and render SVG paths using `d3.line` with a monotone X curve. Axes are generated with `d3.axisBottom` and `d3.axisLeft`, while `d3.scaleTime` and `d3.scaleLinear` map dates and temperatures. A Tableau10 color palette distinguishes city groups via `d3.scaleOrdinal`.