Airport month record
SEAMAR
Seattle-Tacoma International in March 2026
- Departures
- 12,830
- Month
- March 2026
- National, same month
- 75.7%
- Carriers
- 8
Historical statistics for March 2026, not live status or a forecast for this year’s March. For today’s conditions at SEA, see live FAA status.
SEA in March lands a B, 5 points better than the national rate of 75.7%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 12,830 flights, of which SkyWest Airlines flew 2,283 at 84.9% on time.
SkyWest Airlines is the most reliable of the six carriers covered here at 84.9% on time across 2,283 flights.
Key figures
On time
80.2%
Arrivals under 15 minutes late, of 12,505 completed departures
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
2.23%
Nationally in March: 2.90%
Whole year
79.4%
SEA across all twelve months
These figures cover 12,830 departures from Seattle-Tacoma International in March 2026. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.
Against the year
March next to SEA's other months
Against SEA's own year, March ran level with the twelve-month rate of 79.4%, which makes it number eight of twelve months, best first. Cancellations are where March stands out: 2.23% of scheduled departures were called off, 2.3 times the airport's rate across the year. Either side of it, February ran 84.4% on time and April 85.6%, so a trip moved by a few weeks would have landed in a better stretch.
| Month | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| July 2025 | 16,577 | 69.2% | 57 min | 1.38% | C |
| August 2025 | 15,970 | 73.6% | 51 min | 0.66% | C+ |
| September 2025 | 14,552 | 82.9% | 50 min | 0.29% | B+ |
| October 2025 | 13,859 | 82.9% | 58 min | 1.16% | B |
| November 2025 | 12,616 | 81.9% | 58 min | 1.69% | B |
| December 2025 | 13,023 | 74.0% | 59 min | 1.02% | C |
| January 2026 | 11,927 | 81.6% | 60 min | 1.91% | B |
| February 2026 | 11,000 | 84.4% | 56 min | 0.78% | B+ |
| March 2026 (this page) | 12,830 | 80.2% | 64 min | 2.23% | B |
| April 2026 | 12,864 | 85.6% | 56 min | 0.17% | A+ |
| May 2026 | 14,564 | 82.2% | 52 min | 0.41% | B+ |
| June 2026 | 15,402 | 78.1% | 57 min | 0.48% | B+ |
Departure window
The best time of day to leave SEA in March
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 12 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,593 flights88.6%
- 8am–11am2,603 flights82.3%
- 11am–2pm2,444 flights79.1%
- 2pm–5pm1,753 flights78.2%
- 5pm–8pm1,869 flights76.5%
- 8pm–5am2,568 flights77.8%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 88.6% of the time, against 76.5% for the evening window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 2,603 flights scheduled in it.
Across the week, Tuesday is the strongest day at 85.7% on time and Friday the weakest at 68.2%. 18 points is a smaller lever than departure hour, but it is free.
Carrier by carrier
Which airlines ran best at SEA in March
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 84.9% of the time; Southwest Airlines manages 70.0%. Sample sizes sit next to every figure, because a two-point gap across 583 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlines | 6,169 | 79.0% | 55 min | 1.70% | B |
| Delta Air Lines | 2,596 | 79.0% | 69 min | 3.51% | B− |
| SkyWest Airlines | 2,283 | 84.9% | 80 min | 2.28% | B |
| Southwest Airlines | 583 | 70.0% | 51 min | 1.54% | C |
| United Airlines | 561 | 84.5% | 96 min | 1.78% | B |
| American Airlines | 480 | 84.4% | 98 min | 2.92% | B |
| Frontier Airlinesthin sample | 98 | 81.7% | 70 min | 5.10% | B− |
| Envoy Airthin sample | 60 | 90.0% | 76 min | 0.00% | A+ |
Delta Air Lines cancels 3.5% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Busiest routes out of SEA in March
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SEA to PHX · Phoenix | 686 | 80.2% | 64 min | 2.19% | B |
| SEA to LAX · Los Angeles | 639 | 83.6% | 58 min | 2.35% | B |
| SEA to SFO · San Francisco | 528 | 81.7% | 72 min | 2.46% | B |
| SEA to LAS · Las Vegas | 478 | 76.8% | 47 min | 2.72% | B |
| SEA to ANC · Anchorage | 478 | 66.8% | 61 min | 1.05% | C |
| SEA to DEN · Denver | 455 | 79.2% | 70 min | 2.64% | B |
| SEA to GEG · Spokane | 418 | 84.6% | 54 min | 2.15% | B |
| SEA to PDX · Portland | 397 | 79.6% | 68 min | 2.52% | B |
| SEA to SAN · San Diego | 388 | 76.1% | 58 min | 1.80% | B |
| SEA to DFW · Dallas-Fort Worth | 386 | 85.3% | 68 min | 2.85% | A |
| SEA to BOI · Boise | 369 | 84.6% | 64 min | 1.36% | B |
| SEA to ORD · Chicagothin sample | 357 | 79.8% | 103 min | 2.80% | B |
| SEA to SMF · Sacramentothin sample | 350 | 81.0% | 61 min | 2.00% | B |
| SEA to SLC · Salt Lake Citythin sample | 334 | 84.7% | 48 min | 3.59% | B− |
| SEA to SJC · San Josethin sample | 330 | 80.8% | 58 min | 2.12% | B |
| SEA to SNA · Santa Anathin sample | 308 | 83.9% | 61 min | 2.92% | B |
| SEA to HNL · Honoluluthin sample | 260 | 51.6% | 60 min | 0.77% | F+ |
| SEA to ATL · Atlantathin sample | 231 | 80.8% | 63 min | 1.30% | B |
| SEA to JFK · New Yorkthin sample | 214 | 80.8% | 56 min | 2.34% | B |
| SEA to PSP · Palm Springsthin sample | 199 | 77.6% | 58 min | 1.51% | B |
| SEA to MSP · Minneapolisthin sample | 199 | 89.9% | 80 min | 5.03% | A− |
| SEA to FAI · Fairbanksthin sample | 178 | 72.4% | 79 min | 1.69% | C |
| SEA to ONT · Ontariothin sample | 177 | 86.2% | 67 min | 1.69% | A |
| SEA to AUS · Austinthin sample | 172 | 86.9% | 76 min | 2.33% | A |
| SEA to BOS · Bostonthin sample | 172 | 86.5% | 71 min | 0.58% | A+ |
Delay causes
What held SEA up in March
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 158,000 reported delay minutes.
- 37%Carrier
- 29%Late-arriving aircraft
- 19%National Airspace System
- 15%Extreme weather
- 0%Security
Extreme weather accounts for 15% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the comparison with the other months below is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.5 times the usual weather exposure. The split is drawn from 158,343 reported delay minutes.
Cancellations sit at 2.23% against a national 2.90%, which is ordinary. Diversions add another 0.30%.
6.2% of arrivals land an hour or more late, close to the national 9.5%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
What to do with this
Flying from SEA in March
For a March trip through SEA: expect 80.2% on time and 2.23% cancelled, going by March 2026. The 5am–8am window was the strongest part of the day.
Related
Where to go next
- Seattle-Tacoma International (SEA), the whole year
- SEA in July69.2%
- SEA in August73.6%
- SEA in September82.9%
- SEA in October82.9%
- SEA in November81.9%
- SEA in December74.0%
- SEA in January81.6%
- SEA in February84.4%
- SEA in April85.6%
- SEA in May82.2%
- SEA in June78.1%
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.