Which Weather Data You Need for Segment Predictions
A prediction is only as good as its weather data. Segment forecasting needs more than an icon and a daily high.
The mandatory fields
Without these values per hour, no meaningful segment prediction is possible:
- wind speed at 10 m height
- wind direction in degrees
- gust peaks — critical for rideability
- air temperature for air density
- air pressure, optional but useful
Rolling 24 hours, not a calendar day
Planning in the evening means you need tonight and tomorrow morning. A forecast that ends at midnight is useless exactly when you need it. A rolling window starting from the current hour is the right format.
Model resolution beats model name
A model with a few kilometres of grid spacing captures local wind far better than a global model. For Germany, the national weather service data provides an excellent basis; KomPredict uses it through a public interface with a local cache.
Cache and stay robust
Weather interfaces have rate limits and outages. A cache with a bounded lifetime, plus the option to show slightly stale data on failure, keeps the app working when the source briefly stops answering.
In short
Hourly values with direction and gusts are mandatory — and the forecast should start now, not at midnight.
Frequently asked questions
How often should data refresh?
Models typically run hourly. A 30 to 60 minute cache balances freshness against load.
Is a nearby station enough?
For temperature usually yes, for wind rarely — wind is extremely local, and a model grid point often beats a station behind a treeline.