This line chart visualizes monthly average temperatures for four US cities—NYC, LA, Chicago, and Houston—using colored lines (blue, red, green, orange) with corresponding data points. The SVG visualization uses D3 v7 scales and line generators, with a custom tooltip that appears on mouseover to display each city’s temperature for a given month. The code parses CSV data containing temperatures in Fahrenheit, then plots them along a band scale for months and a linear scale for temperature values. Interactive hover circles provide precise data readouts for each city.