This example displays weather data for the two weeks leading up to the 2024 Boston Marathon, showing maximum, minimum, and mean temperatures for each athlete’s registered zip code across fifteen days in April. The visualization initially renders raw CSV data as JSON text, loading and parsing the dataset with `d3.csvParse` within a `fetch` call. The D3 v7 `select` and `join` methods manage the DOM updates asynchronously, with state management handling the transition from loading to populated data.