Products / Windline
Windline
Wind for a whole multi-day tour, timed to the hour the group reaches each stretch of road.
- Relationship
- Windline is an independent product created and operated by Cross Constellation. It is in public beta.
- Canonical site
- windline.tech
- Status
- Active public product
- Product colour
- #635BFF
The one-sentence definition, without comparison or superlative.
What it is
Windline turns a folder of GPX routes into one live link. It reads the distance, climbing and bearing of every stretch of road, works out when the group will reach each one from the start time, riding speed and stops, and forecasts the wind, gusts, rain and heat for that moment. Because it compares wind direction against road direction, it reports headwind and tailwind rather than a compass bearing. Riders install nothing: the link opens in any phone browser and re-forecasts from the newest model run every time it is opened.
The operating frustration that existed before the product.
The problem we encountered
A weather app forecasts one place at one time. A tour covers two hundred kilometres a day, through different weather, at different hours, and the wind at the start tells you nothing about the climb at eleven. The question gets asked in every tour group chat the night before, and nobody has a good answer — the honest reply to “thirty from the west” is “at the start, or at Sutherland?”
The founder’s account, in their own words.
Why we built it
“A tour the founder is riding. Pont Drift to Cape Town, thirteen stages, 2,093 kilometres, in October 2026. It was built to answer the nine o’clock question on that tour, and it is being ridden before it is sold.”
How the first problem expanded into the current product.
What the product became
- Wind resolved against road bearing, so a stretch reports headwind, crosswind or tailwind instead of a compass direction.
- Forecasts timed to arrival rather than to the clock — pace, climbs and stops are modelled, and wind is blended between hourly readings to the moment the group gets there.
- Four models side by side — ECMWF, GFS, ICON and a blend — with disagreement surfaced rather than averaged away.
- One link per tour and one per stage, opening in a phone browser with no account and nothing to install.
Genuine dogfooding. Deployed uses only.
How we use it ourselves
- The founder is riding 2,093 km of the Pont Drift to Cape Town tour on it, in October 2026, before it is offered to anyone else. Deployed
- Every rating on the public tour page is computed in the visitor’s browser from the current forecast, so the product is demonstrating itself rather than showing a recorded result. Deployed
The relationship graph, rendered from the register.
How it connects to the portfolio
Attributable support for everything claimed above.
Where to go for the product itself.
Official destinations
Stories