University of Idaho
Integrated Design Lab

🌬 Wind Rose Diagram

Tool 3 of the IDL Climate Analysis Suite · Brown & DeKay Technique 4

Load Weather Data

Pick an Idaho city below for an instant load, or drop your own EPW file. 8,760 hourly records will be analyzed and plotted as a wind rose by direction and speed bin.

Loading weather data…
or upload your own file
📁
Drag & drop an EPW file here
or click to browse
About the city presets: these load TMYx weather files (typical meteorological year, derived from recent observations) hosted on the IDL server. Some adjacent cities share the nearest airport's station data — Eagle/Kuna use Boise, Post Falls uses Coeur d'Alene, Blackfoot uses Pocatello, Sun Valley/Ketchum uses Hailey. For other locations, free EPW files worldwide are at climate.onebuilding.org.
Wind Rose

Reading this diagram

Each petal points to the direction the wind comes from. The petal's length shows how often wind comes from that direction; concentric rings mark frequency in percent of hours. Bands within each petal break down wind speed from light (innermost) to strong (outermost).

Architectural use: identify prevailing winds for natural ventilation, locate windbreaks against undesirable cold winter winds, and orient buildings to admit summer breezes (Brown & DeKay, Sun, Wind & Light, p. 14–15).