79% of flights from Chicago to Key West arrived on time over the past 12 months. That is about the typical U.S. route. The 8 a.m. departures ran on time 83% of the time; the 11 a.m. ones 72%. Most reliable airline: American Airlines (81%). 9% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for ORD → EYW: when a flight was late, it was under 45 minutes late 50% of the time. About 1 in 15 flights landed an hour or more late, and 1 in 136 three hours or more; 1.3% were cancelled outright.
- On time or early79%
- 15–30 min late6.1%
- 30–60 min late6.5%
- 1–2 hours late4.9%
- 2–3 hours late1.2%
- 3+ hours late0.7%
- Diverted0.5%
- Cancelled1.3%
Share of all 815 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| American Airlines | 465 | 81% | 1.3% | −17 min | 6.9% | +61 min | Envoy 100%, Republic Airways 0% |
| United Airlines | 350 | 76% | 1.4% | −4 min | 6.9% | +61 min | Republic Airways 61%, United Airlines 39% |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at ORD). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | American Airlines | United Airlines |
|---|---|---|
| 8 a.m. | 83% | — |
| 10 a.m. | — | 78% |
| 1 p.m. | 81% | — |
Last flight of the day
On ORD → EYW, each airline's last flight of the day was cancelled 1.8% of the time, against 0.4% for its earlier flights (4.0× as often). It arrived 3+ hours late 1.8% of the time (earlier flights: 0.4%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| American Airlines | 11:22 a.m. | 1.8% | 1.8% | 0.6% | first flight 11:22 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
If you need to be in EYW tonight, book an earlier flight so there's a backup if it's cancelled.
By month
Each calendar month pooled over 2023–2026. Best: May (86%). Worst: December (72%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 113 | 78% | 4.4% |
| Tuesday | 110 | 87% | 0.0% |
| Wednesday | 113 | 83% | 0.0% |
| Thursday | 116 | 78% | 0.0% |
| Friday | 118 | 77% | 0.0% |
| Saturday | 127 | 74% | 1.6% |
| Sunday | 118 | 74% | 3.4% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 9 · airline 1 · air traffic/airport 1
Month by month
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Dec 26, 2025 | 4 | 0% | 0 |
| Dec 18, 2025 | 4 | 0% | 0 |
| Mar 14, 2026 | 4 | 0% | 0 |
| Nov 30, 2025 | 3 | 0% | 1 |
| Mar 16, 2026 | 3 | 0% | 2 |
Questions
How often are flights from ORD to EYW on time?
79% of 815 scheduled flights from Chicago, IL to Key West, FL arrived within 15 minutes of schedule between September 2025 and August 2026. 1.4% were cancelled.
What is the best time of day to fly ORD to EYW?
Flights scheduled to leave at 8 a.m. were the most reliable (83% on time). The 11 a.m. departures were the least (72%).
Which airline is most on time from ORD to EYW?
American Airlines: 81% of its 465 flights on the route arrived on time. United Airlines: 76%.
What month has the most delays from ORD to EYW?
December (72% on time). The best month is May (86%), over 2023–2026.
Is the last flight of the day from ORD to EYW more likely to be cancelled?
Yes. Each airline's last ORD–EYW flight of the day was cancelled 1.8% of the time over the past year, against 0.4% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- EYW → ORD (return)
- Chicago O'Hare (ORD) delays by hour
- Flights into Key West (EYW)
- American Airlines on-time record
- United Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.