This multi-series line chart visualizes daily average temperatures for New York, San Francisco, and Austin over a year, using data loaded from a TSV file via d3.tsv. The x-axis employs a time scale with dates parsed by d3.time.format, while the y-axis uses a linear scale for temperature values. Each city’s temperature series is drawn as a separate colored line using d3.svg.line, with colors assigned from the category10 ordinal scale. The chart computes its x- and y-domains dynamically with d3.extent, d3.min, and d3.max, and uses d3.keys to identify the city columns in the dataset. Conventional margins are applied, and axes are rendered with d3.svg.axis. The visualization compares daily average temperatures across New York, San Francisco, and Austin over one year, highlighting seasonal differences among the three cities.