Aspen Flight Delay Track Record

Every call we make, graded in public.

Every morning, our risk model calls the day at Aspen airport: GREEN, YELLOW or RED. We lock that call before the first flight and never change it. The next morning we grade it against what really happened. Every call is on this page, including the ones we got wrong.

The score so far

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Every day, newest first

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How we grade

A bad day is one where at least 1 in 3 Aspen airline flights was cancelled, diverted, or 60 or more minutes late. On a busy winter day that is about a dozen flights.
RED means we expect a bad day. A RED call on a bad day is “Called it.” A RED call on any other day is a false alarm.
A bad day without a RED call is a miss, even if we said YELLOW.
YELLOW means the risk is up but a bad day is not the most likely outcome. We show YELLOW days, but we do not count them as hits.
The call is the one our model makes at 14:00 UTC, which is 7 am in Aspen in winter and 8 am in summer. That is before the first flight of the day.
The grade comes from the same live flight data our Flight Board uses, checked the next morning. Days with fewer than 6 flights are not graded.
If a call failed to save because our system was down, the day shows “No call logged.” We never add a call after the fact.

What we expect

We tested this same 7 am call on the 2025–26 season, using data the model never saw while it was built. It called RED on 50 of the 56 bad days. It also called RED on some days that turned out fine: about half of its RED calls were false alarms. That trade is on purpose. Missing a bad day costs a traveler far more than an extra warning. This page is where we find out if those numbers hold up in real life.

How to check us

Each call is saved once and cannot be edited. The raw record is public as JSON data. Each morning, right after the call locks, we also ask the Internet Archive to save a copy. Those Wayback Machine copies carry the archive’s own timestamp, so you do not have to take our word for when a call was made.

The runway will close in 2027. From April to November 2027, Aspen’s runway will be closed for the airport modernization project. With no flights there is nothing to grade, so the record pauses and starts again when flights return.

Our calls are forecasts, not airline information. Always check your flight with your airline.