Imagine a day with a ferocious headwind trying to match your time set on a calm windless day. How much more power would you require?
How is it calculated?
Your VR (Virtual Rider) completes the course including climbing and descending hills along the way with zero wind and perfect conditions. Then your VR has to match the speed it set in the first windless attempt whilst battling your actual or forecast weather conditions. The difference in power required by the second to match the first riders speed is the Weather Impact™.
Is wind the only factor tested?
No, we also include a benchmark Air Density in the simulations. In theory a day with a slightly higher wind speed could require less Watts than a day with higher Air Density.
Is it a comparable metric across courses and efforts?
Yes, your Virtual Rider testing the course has a benchmark set up for CdA, weight and power which is independent to your Profile settings. This allows weather conditions and the course to be compared on a level playing field with out setup variance.
What if the conditions are more favourable than benchmark conditions?
Favourable conditions produce a negative Weather Impact™. For example, a headwind would perhaps produce +10% Weather Impact™. However a tailwind would produce a negative such as -10% Weather Impact™.
wImpact% is a Premium Metric. Learn more about Premium here, myWindsock Premium.