Best time to fly out of Chicago Midway (MDW)

The early-flight folk wisdom holds up at Chicago Midway: departures in the Before 6am band left on time 94.1% of the time, against 49.8% in the 10pm–12am band. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.

Data through June 2026 · Bureau of Transportation Statistics

On-time rate by hour and day

On this page, “on time” means a departure that pushed back less than 15 minutes behind its scheduled time — the Bureau of Transportation Statistics definition, and the one airlines are held to.

Share of departures that left on time, by hour band and day of week.
Departure time MonTueWedThuFriSatSun
Before 6am 94 96 96 95 93 93 94
6–8am 90 93 93 93 90 90 92
8–10am 85 88 89 89 83 85 84
10am–12pm 79 84 86 80 78 85 79
12–2pm 75 81 81 77 74 81 74
2–4pm 66 73 72 68 66 72 66
4–6pm 62 71 68 61 63 68 59
6–8pm 63 67 68 59 65 67 56
8–10pm 58 64 64 54 58 50 50
10pm–12am 58 51 52 46 53 53 43
fewer left on time more left on time

The steadiest stretch at MDW was Before 6am — 94.1% of departures left on time across 8,170 flights. The weakest was 10pm–12am at 49.8%. 6–8am departures from MDW left on time 91.3% of the time across 23,308 flights; 6–8pm departures, 63.4% across 28,539. That is a gap of 27.9 points, and it is the whole case for the early flight.

The year at MDW

July was the hard month at MDW: 61.4% of departures left on time, across 23,357 flights. February was the easy one at 83.1%. Each month pools three years of that month, so a single bad week does not decide it.

Share of departures that left on time, by calendar month. Best month in green, worst in amber. The hairline sits at the overall rate, 74.3%.
Departure on-time share at MDW by calendar month
Month Share departures that left on time Flights
January 78.6% 15,923
February 83.1% 14,514
March 72.4% 19,298
April 79% 19,124
May 69.8% 19,370
June 64.6% 21,661
July 61.4% 23,357
August 72.5% 21,820
September 80.5% 20,417
October 79.8% 20,933
November 82.4% 18,266
December 74.2% 18,523

Airlines at MDW

Every airline with at least 100 departures from MDW, busiest first. These are that airline’s departures from this airport only — its record across the country sits on its own page.

Airline Left on time Typical delay Cancelled Departures
Southwest Airlines 73.9% 51 min 1.2% 213,263
Frontier Airlines 74.1% 90 min 2.4% 9,227
SkyWest Airlines 81.9% 89 min 0.6% 5,124
Delta Air Lines 84.6% 90 min 1.6% 4,364
Allegiant Air 77.8% 128 min 0.8% 1,228

What delays out of MDW were put down to

Airlines file a reason with every arrival running 15 minutes late or more. Across 53,615 flights that departed MDW and ran 15 minutes late or more, the delay minutes break down with 43.7% put down to late-arriving aircraft and 33% to airline operations.

Late-arriving aircraft 43.7% Airline operations 33% Air traffic & airport volume 19% Severe weather 4% Security 0.3%
  • Late-arriving aircraft 43.7%
  • Airline operations 33%
  • Air traffic & airport volume 19%
  • Severe weather 4%
  • Security 0.3%

Late-arriving aircraft is the knock-on category: the plane came in late, so it went out late again. It is why a 7am problem in Newark is still a problem in Denver at dinnertime, and why it is usually the biggest slice on the bar.

If you are connecting through MDW

Of 233,209 scheduled arrivals into MDW, 78.5% reached the gate less than 15 minutes behind schedule. Of the 46,328 arrivals that ran late, 60.3% were no more than 45 minutes behind — which is the difference between a tight connection and a new boarding pass.

Work out a specific layover — pick the airport and the minutes you have, and the tool reads the same arrival records back as a share.

Busiest routes out of MDW

Ranked by flights, with the share that arrived on time at the far end. Where a route carries enough flights for a page of its own the chip goes there; otherwise it goes to the destination airport.

MDW in one number

Chicago Midway (MDW)

Rank 29 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: July.

July 2023–June 2026 · 230,390 departures flown

74.3% of departures left on time

Questions about MDW

What is the best time of day to fly out of Chicago Midway?
Before 6am. Departures in that band left on time 94.1% of the time across 8,170 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 10pm–12am band was the weakest at 49.8%.
Is the early flight out of MDW really more reliable?
6–8am departures from MDW left on time 91.3% of the time across 23,308 flights; 6–8pm departures, 63.4% across 28,539. That is a gap of 27.9 points, and it is the whole case for the early flight.
What is the worst month to fly out of MDW?
July: 61.4% of the departures that flew left on time, with 23,357 scheduled. February was the other end of the year at 83.1%. Each figure pools three years of that calendar month.
Which airline is most on time at MDW?
Delta Air Lines — 84.6% of its 4,364 departures from MDW left on time. Southwest Airlines sat at the other end at 73.9% over 213,263 flights. Only airlines with at least 100 departures here are ranked.
How often are flights cancelled at MDW?
1.2% of scheduled departures were cancelled over July 2023 through June 2026. Cancellations are counted against everything scheduled, not against everything that flew — a rate that looks small still adds up to real people in a rebooking line.