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Route Reliability

Seattle → Ontario

SEA–ONT · 956 miles · Seattle–Tacoma International Airport to Ontario International Airport

86
Pretty Reliable
WanderNerd Reliability Score
83%
Arrive within 15 minutes
2 min
Average arrival delay
1.2%
Cancelled
2,577
Flights in the data

Data through May 2026.

Who flies it best

Ranked by on-time arrivals. Historical results, not predictions.

  1. 1.Delta Air Lines90%1,141 flights
  2. 2.Alaska Airlines77%1,265 flights
  3. 3.Frontier Airlines76%171 flights

What the data says

Morning-you made the right choice.

SEA–ONT flights departing between 6–9 AM arrived on time 91% of the time, versus 67% between 9 PM–12 AM.

Tuesday has been the better bet.

A small edge: 85% on time on Tuesdays against 79% on Fridays.

Delta Air Lines runs this route best.

Delta Air Lines arrived on time 90% of the time on this route; Frontier Airlines managed 76%.

Trending in the right direction.

SEA–ONT flights arrived on time 88% of the time over the last three months in the data, compared with 81% in the three months before that.

Best historical flights

Ranked by on-time arrivals, minimum 100 flights. Past performance, not a promise.

Top flights by on-time rate

More flights on this route

The breakdown

On-time by weekday
  • Mon83%(387 flights)
  • Tue85%(355 flights)
  • Wed83%(345 flights)
  • Thu81%(367 flights)
  • Fri79%(373 flights)
  • Sat85%(323 flights)
  • Sun82%(397 flights)
On-time by departure window
  • 6–9 AM91%(600 flights)
  • 9 AM–12 PM85%(346 flights)
  • 12–3 PM82%(627 flights)
  • 3–6 PM69%(250 flights)
  • 6–9 PM86%(494 flights)
  • 9 PM–12 AM67%(230 flights)
On-time trend by month
87%
May

Jun 77% → May 87% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202577%265
July 202572%292
August 202579%265
September 202591%213
October 202588%198
November 202584%204
December 202573%198
January 202685%156
February 202684%135
March 202687%174
April 202690%200
May 202687%247

Same trip, other airports

Keep nerding

Based on 2,577 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.