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Route · SEA → SLC · 2020–2025 BTS data

Seattle to Salt Lake City

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to SLC (Seattle to Salt Lake City) ranks #259 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

85.1%
On-time
+6.1 pts
vs US avg
58 min
Delay when late
22,743
Flights
#259 of 4927
Corpus placement

Cancelled

0.8%

Best Month

Jan 2025 90%

Worst Month

Jul 2024 76%

Distance

689 mi

Carriers

22

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 305 71 2 0 DL,F9,AS,OO
Nov 2025 297 36 8 0 OO,DL,F9,AS
Oct 2025 365 52 5 0 AS,DL,OO,F9
Sep 2025 398 44 1 0 OO,DL,F9,AS
Aug 2025 408 91 4 0 OO,F9,AS,DL
Jul 2025 394 91 4 1 AS,DL,OO,F9
Jun 2025 371 87 2 0 AS,OO,DL,F9
May 2025 361 66 1 0 AS,OO,DL,F9
Apr 2025 306 46 0 0 DL,F9,OO,AS
Mar 2025 306 47 1 0 AS,OO,DL,F9
Feb 2025 280 43 3 0 AS,OO,DL,F9
Jan 2025 320 33 0 0 AS,OO,DL,F9
Dec 2024 303 35 1 1 AS,DL,F9,OO
Nov 2024 318 33 1 0 OO,AS,DL,F9
Oct 2024 335 35 1 0 AS,OO,DL,F9
Sep 2024 366 52 0 0 OO,AS,DL
Aug 2024 384 83 2 0 AS,DL,OO
Jul 2024 397 96 10 0 AS,DL,OO
Jun 2024 382 68 0 0 AS,DL,OO
May 2024 365 43 0 0 AS,DL,OO
Apr 2024 306 37 0 0 AS,DL,OO
Mar 2024 274 57 1 0 AS,DL,OO
Feb 2024 268 36 0 0 AS,DL,OO
Jan 2024 287 66 14 0 AS,DL,OO

SEA–SLC seasonal on-time pattern

Best: April (89.3%) · weakest: August (80.1%)

75%80%85%90% JanFebMarAprMayJunJulAugSepOctNovDec 81.9%

Strongest calendar month

April

89.3% on-time · ~282 flights/mo

Busiest calendar month

August

~361 flights/mo avg

Weakest calendar month

August

80.1% on-time · ~361 flights/mo

Cancellation Rate

0.8%

61 of 8,096 flights

Diversion Rate

0.0%

2 of 8,096 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

SLC - Salt Lake City

Full on-time, delay-cause, and seasonal performance for Salt Lake City, UT.

SLC on-time profile

Compare the two airports

See SEA and SLC side by side on delays, cancellations, and reliability.

Compare SEA vs SLC

Origin-hub reliability standing

Among SEA's stronger departures

SEA → SLC posts a 85.1% on-time rate, landing in the ≥85% band with 25 of 89 BTS-tracked routes leaving Seattle. The same hub also shows 63 mid-band and 1 challenged departures · fleet-wide on-time rank #1195 of 4927 (highest on-time = #1).

What the Data Says About SEA to SLC

Seattle to Salt Lake City (SEA to SLC) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 85.1% on-time rate across 22,743 flights, with delays that do happen averaging 58.4 minutes. The corridor runs roughly 689 miles and is served by 22 carriers. Over the most recent 24 months, 61 of 8,096 flights were cancelled (0.8%) and 2 diverted (0.0%).

Monthly performance varies moderately here: Jan 2025 was the strongest month at 90% on-time versus Jul 2024 at 76%, a 14-point difference.

On the multi-year calendar, SEA–SLC peaks in April at 89.3% on-time while August carries the heaviest traffic (~361 flights per month) ; the softest month is August at 80.1%, a 9.2-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to SLC rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to SLC ranks #259 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from SEA to SLC? ▼
Flights from Seattle to Salt Lake City have a 85.1% on-time rate based on 22,743 flights. The average delay is 58.4 minutes. The best recent month was Jan 2025 with 90% on-time.
What is the cancellation rate for SEA to SLC? ▼
Over the last 24 months, 0.8% of flights on this route were cancelled (61 of 8,096 flights) and 0.0% were diverted.
How far is the flight from SEA to SLC? ▼
The flight distance from Seattle (SEA) to Salt Lake City (SLC) is approximately 689 miles. This route is served by 22 carriers.
When is the best time to fly from SEA to SLC? ▼
The best recent month for on-time performance was Jan 2025 (90% on-time). The worst was Jul 2024 (76% on-time). Consider booking during months with historically better performance.

Airports on this route

SEA Airport

Seattle
SLC Airport

Salt Lake City
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 SEA–SLC data

SEA–SLC runs 6.1 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare SEA and SLC airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, April (89.3% on-time) beats August (80.1%) on this corridor. Seasonal chart
  • 4 other routes post a similar 85.1% 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.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

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.