Observed arrival · 2026-09-09
Headwind Pace, a race calculator that notices the weather
A running calculator estimates race times and kilometre splits using fitness, heat, humidity, wind, elevation, altitude, body size, and optional GPX course data.
Field notes
The calculator starts with a recent race result or average pace, then layers on weather and course conditions. Users can type elevation and altitude or upload a GPX track, while the page says wind is evaluated in both directions when course bearing is unknown. Its heat model varies the penalty by runner speed, citing an approximate range from 0.6 to 2.8 seconds per kilometre per degree; the author also labels the final output an order-of-magnitude estimate rather than an exact prediction.
Observed signals
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Editorial observations of this landing page, not a rating.
One card from the complete issue