Route Reliability

Route reliability

Chicago (ORD) to San Diego (SAN): which airline is most on time?

On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from Chicago, IL (ORD) to San Diego, CA (SAN), September 2025 to August 2026.

Historical performance Official DOT data through August 2026 · Not live flight status

Chicago, ILSan Diego, CA

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Three-letter airport codes, nonstop U.S. domestic flights. One direction at a time.

Route at a glance · September 2025 to August 2026

ORD to SAN

Chicago, IL to San Diego, CA

On time
69.3%vs 75.6% U.S. average Worse than average
Cancelled
1.3%vs 1.9% U.S. average Better than average
60+ min late
10.0%vs 8.1% U.S. average Worse than average
Scheduled flights
3,945in 12 months4 airlines
Most reliable airline
United Airlines75.7% on time · 1,677 flights

On time less often than the U.S. average, with fewer cancellations.

Compared with all U.S. flights, September 2025 to August 2026. “About average” means within 1.5 points for on time, 0.3 for cancelled and 1 for 60+ minutes late.

Airlines on this route

Ranked by on-time arrival

Airlines from ORD to SAN, September 2025 to August 2026. Rates are shares of all scheduled flights.
Airline On time Cancelled 60+ min late Avg delay when late Diverted Flights
1. United Airlines Most reliable 75.7% 0.4% 6.9% 62 min 0.5% 1,677
2. Alaska Airlines 66.8% 2.6% 10.8% 73 min 0.1% 862
3. American Airlines 63.1% 1.6% 13.2% 64 min 0.3% 1,400
Frontier Airlines Insufficient sample (fewer than 50 flights) 6

On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.

What this means

United Airlines has the strongest record on this route.

  • United Airlines had the best on-time record from Chicago (ORD) to San Diego (SAN): 75.7% of its 1,677 scheduled flights arrived within 15 minutes of schedule, compared with 63.1% for American Airlines.
  • Frontier Airlines also flew this route but with fewer than 50 reported flights, too few to rate.
  • 1.3% of flights on this route were cancelled (about 1 in 77), 0.6 points lower than the U.S. average of 1.9%.
  • 10.0% of flights, about 1 in 10, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 65 min.
  • Overall, 69.3% of flights on this route arrived on time, 6.3 points lower than the U.S. average of 75.6%.
  • Over the last 3 years, October was the most reliable month on this route (79.2% on time) and August the least reliable (66.2%).
  • Cancellations peaked in January, when 3.7% of flights were cancelled.
  • Flights scheduled to depart 7 am to 8 am were the most punctual (89.2% on time); flights scheduled to depart 9 pm to 10 pm were the least (40.5%).
  • In the other direction, San Diego (SAN) to Chicago (ORD), 75.5% of flights were on time and 1.3% were cancelled. Compare airlines SAN to ORD.

Best and worst months to fly ORD to SAN

Jan 73.4%
Feb 78.1%
Mar 78.7%
Apr 72.2%
May 75.1%
Jun 67.7%
Jul 67.3%
Aug 66.2%
Sep 79.1%
Oct 79.2%
Nov 75.6%
Dec 73.3%
Share of scheduled flights on time 12-month average 69.3%
All airlines combined, by calendar month, September 2023 to August 2026 (3 years pooled). Scale starts at zero.
Show as table
PeriodOn timeFlights
January 73.4% 647
February 78.1% 597
March 78.7% 767
April 72.2% 831
May 75.1% 887
June 67.7% 964
July 67.3% 1,026
August 66.2% 1,004
September 79.1% 747
October 79.2% 856
November 75.6% 721
December 73.3% 750
Best and worst calendar month by airline, September 2023 to August 2026.
AirlineBest monthWorst month
United Airlines March (85.9%) August (67.2%)
Alaska Airlines February (87.5%) November (47.7%)
American Airlines October (78.8%) April (61.8%)

Month by month, last 12 months

Sep 76.7%
Oct 73.1%
Nov 66.4%
Dec 61.7%
Jan 71.8%
Feb 76.0%
Mar 73.2%
Apr 62.5%
May 76.6%
Jun 67.1%
Jul 71.4%
Aug 59.5%
Share of scheduled flights on time U.S. average 75.6%
All airlines combined, September 2025 to August 2026. Scale starts at zero.
Show as table
PeriodOn timeFlights
Sep 2025 76.7% 270
Oct 2025 73.1% 357
Nov 2025 66.4% 318
Dec 2025 61.7% 308
Jan 2026 71.8% 248
Feb 2026 76.0% 242
Mar 2026 73.2% 332
Apr 2026 62.5% 333
May 2026 76.6% 364
Jun 2026 67.1% 380
Jul 2026 71.4% 398
Aug 2026 59.5% 395

Best and worst departure times

6a 87.1%
7a 89.2%
8a 80.3%
9a 69.2%
10a 67.8%
11a 66.5%
12p 67.7%
1p 78.6%
2p 61.0%
3p 70.6%
4p 63.0%
5p 66.0%
6p 61.6%
7p 54.1%
8p 61.1%
9p 40.5%
Share of scheduled flights on time
By scheduled local departure hour at ORD, September 2025 to August 2026. Hours with no scheduled flights are omitted. Scale starts at zero.
Show as table
PeriodOn timeFlights
Departing 6 am to 7 am 87.1% 186
Departing 7 am to 8 am 89.2% 415
Departing 8 am to 9 am 80.3% 432
Departing 9 am to 10 am 69.2% 308
Departing 10 am to 11 am 67.8% 230
Departing 11 am to noon 66.5% 200
Departing noon to 1 pm 67.7% 65
Departing 1 pm to 2 pm 78.6% 290
Departing 2 pm to 3 pm 61.0% 123
Departing 3 pm to 4 pm 70.6% 170
Departing 4 pm to 5 pm 63.0% 392
Departing 5 pm to 6 pm 66.0% 159
Departing 6 pm to 7 pm 61.6% 138
Departing 7 pm to 8 pm 54.1% 442
Departing 8 pm to 9 pm 61.1% 247
Departing 9 pm to 10 pm 40.5% 148
Woman at an airport window watching a plane take off
Photo: Depositphotos (licensed stock, illustrative only). Credits

Sources & data dates

Source
U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
Period
September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
Data through
August 2026
Processed
2026-11-03
Scope
Nonstop scheduled flights from Chicago, IL (ORD) to San Diego, CA (SAN), one direction. Airlines that report to the DOT only.
Method
Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.

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