MDW to SEA flight delays & on-time performance
Nonstop flights from Chicago Midway International Airport to Seattle–Tacoma International Airport · 1,733 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at MDW or SEA right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Chicago (MDW) to Seattle (SEA) arrived on time 64% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 0.6% were cancelled, and 10% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- Departures scheduled around 8am did best (78% on time); around 5pm did worst (49%).
- Wednesday was the most reliable day to fly (76% on time) and Friday the least (53%).
- The largest source of delay minutes was late-arriving aircraft (47%).
Which airline is most on time from MDW to SEA?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 64% | 0.6% | 20 min | 9.5% | 678 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 7am71%24 flights
- 8am78%59 flights
- 9am75%16 flights
- 10am69%191 flights
- 11am57%14 flights
- 12pm73%44 flights
- 2pm60%25 flights
- 4pm46%13 flights
- 5pm49%75 flights
- 6pm60%10 flights
- 9pm58%157 flights
- 10pm53%36 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday59%1.0% cancelled
- Tuesday69%0.0% cancelled
- Wednesday76%0.0% cancelled
- Thursday57%1.0% cancelled
- Friday53%1.0% cancelled
- Saturday70%1.1% cancelled
- Sunday61%0.0% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Late-arriving aircraft47%
- Airline (crew, maintenance, cleaning, fueling)23%
- Air traffic control & airport congestion22%
- Extreme weather6%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather100%
- Airline (crew, maintenance, cleaning, fueling)0%
- Air traffic control & airport congestion0%
- Security0%
MDW to SEA: common questions
- How often are MDW to SEA flights on time?
- 64% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Chicago to Seattle cancelled?
- 0.6% of scheduled flights were cancelled (4 of 678).
- How long are typical delays?
- Across all flights the average arrival delay was 20 min (early arrivals count as zero). Flights that were late arrived 52 min behind schedule on average, and 9.5% of flights were an hour or more late.
- How long is taxi time at MDW?
- Flights on this route spent 16 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SEA to MDW — 81% on time
More flights from Chicago
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: MDW → SEA, nonstop flights by US airlines that report to the DOT. How we calculate this.