mev windhistory is an amazing resource. Thanks for the link.

I've spent 90 seconds looking at the IEM site. Very easy to grab hourly historical observations for thousands of weather stations. It is definitely feasible (and even perhaps realistic) to whip a script to pull wind data (and temperature and rain, why not) and compute a weather profile for a given route at a given time.

I have a question : Suppose that I ride at 16 kmh (10 mph) due south and the true wind blows from the east at 16 kmh. The apparent wind would be from the south-east at 22.6 kmh. What is the equivalent headwind speed? (my trig is rusty ). More generally, I'll get data on wind speed and direction in 22.5 degrees increments (N NE E, etc.). I'll generate a rough estimate of my direction of travel and compute the resulting headwind velocity, assuming constant speed, Sum across distance. For known dates, based on historical data of the past few years. Which will generate a compact metric allowing to better decide between alternative routes. Should be fun