This multi-series line chart shows monthly climate trends for temperature, rainfall, and humidity from a CSV dataset, with each series color-coded via D3’s `scaleOrdinal` and `schemeSet2`. It uses the `d3.line` generator to draw three overlaid paths, and `d3.axisLeft` with negative tick sizes to create subtle gridlines. Data is aggregated by month using `d3.rollups` and `d3.mean`. A circle annotation highlights the peak temperature point, while legend and axis labels clarify the scales.