"风向频率图" can be translated as "wind direction frequency diagram" or "wind rose diagram" (a more specific and commonly used term in meteorology and related fields).
"Wind direction frequency diagram" directly describes the purpose of the chart, showing how frequently winds blow from different directions.
"Wind rose diagram" is a more technical and widely recognized term in meteorology, aviation, and environmental science. It visually represents the frequency and intensity of winds from various directions, often resembling a rose with petals indicating different wind directions and their frequencies.
In most professional or academic contexts, "wind rose diagram" would be the preferred choice.