This pie chart visualizes weather data by aggregating and summing values for each weather category, then displaying the proportional shares as colored arcs. The chart uses D3 v7 to load CSV data via `d3.csv`, compute category sums with `d3.sum`, and generate the pie layout with `d3.pie()` and `d3.arc()`. A categorical color scale (`d3.scaleOrdinal` with `schemeCategory10`) maps each category to a distinct color, while a legend, positioned dynamically, identifies each slice. The visualization renders as SVG, with white strokes separating arcs for clarity, and includes a title and centered layout.