Reading Confidence Intervals in Time Predictions
"3:01" sounds precise but is misleading. "2:56 to 3:03" tells you how confidently you can plan.
Where the width comes from
The band comes from input uncertainty: wind forecast, daily form, execution and surface. The further ahead the forecast and the windier it is, the wider it gets.
Typical widths
On a three-minute segment these are realistic magnitudes:
- current hour, calm weather: ±3 to 5 seconds
- in 6 hours, moderate wind: ±6 to 10 seconds
- tomorrow, strong wind: ±12 seconds and more
What the confidence value says
A confidence value bundles three things: forecast stability, the volume of your own comparable rides, and model calibration. High values mean the prediction is dependable — not that the time is fast.
Two numbers together make the decision: a good expected time with high confidence is a reason to get the bike out. A good time with low confidence is a reason to wait out the morning and look again.
In short
Use the band, not the number — and let confidence help decide when you set off.
Frequently asked questions
Should I target the lower bound?
No. The lower bound is a best case that happens in roughly one attempt in ten. Plan with the expected value.
Does the band narrow with more rides?
Yes, because calibration improves. The weather-driven part remains.