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Route on-time record

ORD to STL: most on-time flights and the best time to fly

Chicago (Chicago O'Hare International Airport) to St Louis (St. Louis Lambert International Airport). 3,058 nonstop flights in Jun 2025 to May 2026, 70% arrived within 15 minutes and 2.6% were cancelled. The most reliable flight number was Republic 3694 at 7:00 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

ORD → STL

Chicago to St Louis: 3,058 nonstop flights a year

On time (12 months)

70%

Cancelled

2.6%

avg delay 23 min

Best time to leave

9 AM to noon

77% on time vs 56% after 9 PM

Most reliable airline

Republic

75% chance on time

Check ORD to STL fares

Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

  1. #1 · Republic 3694 · sold as American Eagle, Delta Connection or United Express

    7:00 AM → 8:25 AM1h 25m nonstop

    Local times, typical schedule. Last flown 2026-04-29.

    83%

    chance on time

    On time (history)
    86%
    Cancelled
    0.0%
    Avg arrival delay
    8 min
    • Arrived on time 86% of the time (21 flights, Jun 2025 to May 2026).
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (21 flights), so its score leans on the airline's record at this hour.

    Limited track record · 21 flights

    Find 7:00 AM flight fares Opens this date on Aviasales

  2. #2 · Envoy 4104 · sold as American Eagle

    7:05 AM → 8:32 AM1h 27m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    82%

    chance on time

    On time (history)
    91%
    Cancelled
    0.0%
    Avg arrival delay
    3 min
    • Arrived on time 91% of the time (11 flights, Jun 2025 to May 2026).
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (11 flights), so its score leans on the airline's record at this hour.

    Limited track record · 11 flights

    Find 7:05 AM flight fares Opens this date on Aviasales

  3. #3 · Envoy 3870 · sold as American Eagle

    6:59 AM → 8:24 AM1h 25m nonstop

    Local times, typical schedule. Last flown 2026-05-20.

    81%

    chance on time

    On time (history)
    88%
    Cancelled
    0.0%
    Avg arrival delay
    8 min
    • Arrived on time 88% of the time (41 flights, Jun 2025 to May 2026).
    • Never cancelled in 43 scheduled flights.
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (41 flights), so its score leans on the airline's record at this hour.

    Limited track record · 41 flights

    Find 6:59 AM flight fares Opens this date on Aviasales

  4. #4 · Envoy 3815 · sold as American Eagle

    12:40 PM → 2:06 PM1h 26m nonstop

    Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Envoy 3622; its record covers all of them.

    81%

    chance on time

    On time (history)
    85%
    Cancelled
    0.0%
    Avg arrival delay
    9 min
    • Arrived on time 85% of the time (41 flights, Jun 2025 to May 2026).
    • Never cancelled in 41 scheduled flights.
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (41 flights), so its score leans on the airline's record at this hour.

    Limited track record · 41 flights

    Find 12:40 PM flight fares Opens this date on Aviasales

  5. #5 · Republic 4460 · sold as American Eagle, Delta Connection or United Express

    7:20 AM → 8:51 AM1h 31m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    80%

    chance on time

    On time (history)
    79%
    Cancelled
    9.5%
    Avg arrival delay
    12 min
    • Arrived on time 79% of the time (19 flights, Jun 2025 to May 2026).
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (19 flights), so its score leans on the airline's record at this hour.

    Limited track record · 19 flights

    Find 7:20 AM flight fares Opens this date on Aviasales

  6. #6 · Envoy 3868 · sold as American Eagle

    12:24 PM → 1:43 PM1h 19m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    80%

    chance on time

    On time (history)
    85%
    Cancelled
    9.1%
    Avg arrival delay
    12 min
    • Arrived on time 85% of the time (20 flights, Jun 2025 to May 2026).
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • Short track record (20 flights), so its score leans on the airline's record at this hour.

    Limited track record · 20 flights

    Find 12:24 PM flight fares Opens this date on Aviasales

  7. #7 · Republic 4537 · sold as American Eagle, Delta Connection or United Express

    2:58 PM → 4:30 PM1h 32m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    79%

    chance on time

    On time (history)
    91%
    Cancelled
    0.0%
    Avg arrival delay
    3 min
    • Arrived on time 91% of the time (11 flights, Jun 2025 to May 2026).
    • Departs inside ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
    • Short track record (11 flights), so its score leans on the airline's record at this hour.

    Limited track record · 11 flights

    Find 2:58 PM flight fares Opens this date on Aviasales

  8. #8 · Envoy 3714 · sold as American Eagle

    4:40 PM → 6:00 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-04-05.

    77%

    chance on time

    On time (history)
    80%
    Cancelled
    9.1%
    Avg arrival delay
    12 min
    • Arrived on time 80% of the time (20 flights, Jun 2025 to May 2026).
    • Departs inside ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
    • 68% of its delay minutes came from the plane arriving late from an earlier flight.
    • Short track record (20 flights), so its score leans on the airline's record at this hour.

    Limited track record · 20 flights

    Find 4:40 PM flight fares Opens this date on Aviasales

  9. #9 · SkyWest 5214 · sold as United Express, Delta Connection, American Eagle or Alaska

    3:03 PM → 4:39 PM1h 36m nonstop

    Local times, typical schedule. Last flown 2026-05-20.

    75%

    chance on time

    On time (history)
    95%
    Cancelled
    0.0%
    Avg arrival delay
    16 min
    • Arrived on time 95% of the time (21 flights, Jun 2025 to May 2026).
    • Departs inside ORD's trouble window: 44% of its 243 ground stops and delay programs started between 2 PM and 8 PM.
    • 96% of its delay minutes came from the plane arriving late from an earlier flight.
    • Short track record (21 flights), so its score leans on the airline's record at this hour.

    Limited track record · 21 flights

    Find 3:03 PM flight fares Opens this date on Aviasales

  10. #10 · United 1355

    10:40 AM → 12:11 PM1h 31m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    74%

    chance on time

    On time (history)
    91%
    Cancelled
    0.0%
    Avg arrival delay
    11 min
    • Arrived on time 91% of the time (11 flights, Jun 2025 to May 2026).
    • Leaves in this route's most on-time window (9 AM to noon: 77% on time; After 9 PM: 56%).
    • Departs outside ORD's trouble window (2 PM to 8 PM, when 44% of its 243 ground stops and delay programs started).
    • 88% of its delay minutes came from the plane arriving late from an earlier flight.

    Limited track record · 11 flights

    Find United 1355 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

  • Republic Airways (sold as American Eagle, Delta Connection or United Express)75%

    437 flights · 77% on time as flown · 2.4% cancel

  • Envoy Air (sold as American Eagle)74%

    699 flights · 76% on time as flown · 2.2% cancel

  • United Airlines68%

    498 flights · 70% on time as flown · 1.5% cancel

  • SkyWest Airlines (sold as United Express, Delta Connection, American Eagle or Alaska)64%

    862 flights · 67% on time as flown · 3.9% cancel

  • American Airlines63%

    562 flights · 65% on time as flown · 2.1% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

  • Before 9 AM76%

    409 flights · avg delay 14 min

  • 9 AM to noon77%

    318 flights · avg delay 17 min

  • Noon to 3 PM76%

    1,005 flights · avg delay 17 min

  • 3 to 6 PM66%

    466 flights · avg delay 29 min

  • 6 to 9 PM63%

    521 flights · avg delay 25 min

  • After 9 PM56%

    339 flights · avg delay 43 min

Best day: Saturday (80%). Worst: Sunday (71%).

Smarter routing

Nearby airports that run more on time

  • MDW → STL 81% chance on time

    Chicago Midway International Airport to St. Louis Lambert International Airport · 1,705 flights a year · 15 mi from your airports · yours: 69%

    Rank flightsFares

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

J
72
F
79
M
75
A
78
M
77
J
73
J
67
A
74
S
82
O
81
N
81
D
75

What delays this route

  • Late-arriving aircraft42%
  • Airline (crew, maintenance, boarding)34%
  • Air traffic control and airport volume13%
  • Severe weather11%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

ORD to STL questions

What time of day is best to fly ORD to STL?
9 AM to noon: 77% of flights arrived on time, against 56% for departures after 9 PM.
Which airline is most on time from ORD to STL?
Republic, with a season-adjusted 75% chance of operating and arriving on time over 437 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on ORD to STL?
July (67% on time); the best was September (82%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?
No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

More routes from ORD

Live status: FAA delays and ground stops