I rode into 35km/hr head wind for a 15 mile ride on saturday ....I went more than 3/4 of the distance on my return trip on good cycle roads, but it took 1 1/2 hrs ... I had heavy traffic through one stretch of the city .... I actually got off and pushed my bike through christmas shoppers

going there earlier in the morning, I covered the same distance/route in 67 minutes .... not much traffic as it was early .... (very light wind of 6km/hr on my back ... it was a 30 mile commute (15 miles one way) ,I rode to work, then worked for 3 hrs and rode back)

good excercise as where I live, there are few hills... I'm not sure how it would have panned out with a 35km/hr side wind though