Route · MDW → SEA · 2020–2025 BTS data
Chicago to Seattle
According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), MDW to SEA (Chicago to Seattle) ranks #3257 of 4927 tracked domestic routes by total flights (most flights = #1).
Data updated 2026-06-13
- 73.3%
- On-time
- -5.7 pts
- vs US avg
- 51 min
- Delay when late
- 3,110
- Flights
- #3257 of 4927
- Corpus placement
Cancelled
0.4%
Best Month
Sep 2025 79%
Worst Month
Jun 2024 55%
Distance
1,733 mi
Carriers
1
Monthly Performance
Recent 24 months of route data.
| Period | Flights | Delayed | Cancelled | Diverted | Carriers |
|---|---|---|---|---|---|
| Dec 2025 | 31 | 14 | 0 | 1 | WN |
| Nov 2025 | 30 | 11 | 1 | 0 | WN |
| Oct 2025 | 33 | 6 | 0 | 0 | WN |
| Sep 2025 | 86 | 18 | 0 | 0 | WN |
| Aug 2025 | 88 | 30 | 0 | 1 | WN |
| Jul 2025 | 88 | 36 | 1 | 1 | WN |
| Jun 2025 | 78 | 33 | 0 | 1 | WN |
| May 2025 | 31 | 8 | 0 | 1 | WN |
| Apr 2025 | 30 | 3 | 0 | 0 | WN |
| Mar 2025 | 31 | 12 | 0 | 0 | WN |
| Jan 2025 | 31 | 8 | 0 | 0 | WN |
| Dec 2024 | 31 | 8 | 0 | 0 | WN |
| Nov 2024 | 30 | 4 | 0 | 0 | WN |
| Oct 2024 | 35 | 10 | 0 | 0 | WN |
| Sep 2024 | 85 | 24 | 0 | 1 | WN |
| Aug 2024 | 88 | 39 | 0 | 1 | WN |
| Jul 2024 | 88 | 28 | 2 | 0 | WN |
| Jun 2024 | 80 | 36 | 1 | 4 | WN |
| May 2024 | 31 | 11 | 0 | 2 | WN |
| Apr 2024 | 30 | 7 | 0 | 0 | WN |
| Mar 2024 | 31 | 10 | 0 | 0 | WN |
| Jan 2024 | 31 | 11 | 0 | 0 | WN |
| Dec 2023 | 31 | 3 | 0 | 0 | WN |
| Nov 2023 | 32 | 3 | 0 | 0 | WN |
MDW–SEA seasonal on-time pattern
Best: February (83.7%) · weakest: December (64.5%)
Strongest calendar month
February
83.7% on-time · ~49 flights/mo
Busiest calendar month
July
~74 flights/mo avg
Weakest calendar month
December
64.5% on-time · ~31 flights/mo
Cancellation Rate
0.4%
5 of 1,180 flights
Diversion Rate
1.1%
13 of 1,180 flights
Explore origin & destination
On-time and delay data for the airports this route connects.
MDW - Chicago
Full on-time, delay-cause, and seasonal performance for Chicago, IL.
MDW on-time profileSEA - Seattle
Full on-time, delay-cause, and seasonal performance for Seattle, WA.
SEA on-time profileCompare the two airports
See MDW and SEA side by side on delays, cancellations, and reliability.
Compare MDW vs SEAOrigin-hub reliability standing
Softer reliability from MDW
Among 69 routes leaving MDW, only 18 (including this one) clear below 75% on-time, while 0 stay ≥85% and 51 sit mid-band. Travelers comparing MDW options should weigh this 73.3% print against those peers · fleet on-time rank #4658 of 4927.
Similar routes
Other BTS-tracked routes with comparable performance or trip length to MDW–SEA.
Routes with a similar on-time rate
What the Data Says About MDW to SEA
On-time performance on the MDW to SEA pairing (Chicago to Seattle) trails a chunk of the network: 73.3% of 3,110 tracked flights arrived on schedule, with a 51.3-minute average delay on the ones that ran late. The route spans about 1,733 miles across 1 carrier. Cancellations over the trailing 24 months hit 0.4% (5 of 1,180 flights), with 1.1% diverted.
The monthly split is wide on this route: Sep 2025 posted the strongest performance at 79% on-time, while Jun 2024 came in at just 55% - a 24-point swing worth factoring into travel timing.
On the multi-year calendar, MDW–SEA peaks in February at 83.7% on-time while July carries the heaviest traffic (~74 flights per month) ; the softest month is December at 64.5%, a 19.2-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.
Frequently Asked Questions
Where does MDW to SEA rank among US routes by traffic? ▼
How often are flights delayed from MDW to SEA? ▼
What is the cancellation rate for MDW to SEA? ▼
How far is the flight from MDW to SEA? ▼
When is the best time to fly from MDW to SEA? ▼
Airports on this route
Data source
Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.
Read our methodology - how this data is sourced, computed, and verified.
Using MDW–SEA data
MDW–SEA sits 5.7 pts below the national 79% average; check the seasonal chart and airport profiles before treating the headline as typical.
- Compare MDW and SEA airport profiles: delay causes and top routes differ even on the same corridor. MDW airport
- If your dates flex, February (83.7% on-time) beats December (64.5%) on this corridor. Seasonal chart
- 4 other routes post a similar 73.3% on-time rate; compare before you commit to this pairing. Similar routes
On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.
Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.