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Route · ONT → SJC · 2020–2025 BTS data

Ontario to San Jose

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), ONT to SJC (Ontario to San Jose) ranks #1549 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

86.8%
On-time
+7.8 pts
vs US avg
57 min
Delay when late
7,951
Flights
#1549 of 4927
Corpus placement

Cancelled

0.2%

Best Month

Oct 2024 97%

Worst Month

Jul 2025 77%

Distance

333 mi

Carriers

1

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 118 11 1 0 WN
Nov 2025 118 19 0 0 WN
Oct 2025 110 24 0 0 WN
Sep 2025 107 15 0 0 WN
Aug 2025 110 13 0 0 WN
Jul 2025 118 27 0 0 WN
Jun 2025 115 18 0 0 WN
May 2025 123 18 0 0 WN
Apr 2025 114 11 0 0 WN
Mar 2025 107 11 0 0 WN
Feb 2025 99 6 0 0 WN
Jan 2025 102 9 1 0 WN
Dec 2024 108 16 0 0 WN
Nov 2024 109 11 0 0 WN
Oct 2024 123 4 0 0 WN
Sep 2024 132 17 1 0 WN
Aug 2024 134 16 0 0 WN
Jul 2024 116 16 1 0 WN
Jun 2024 115 14 0 0 WN
May 2024 108 24 0 0 WN
Apr 2024 104 15 0 0 WN
Mar 2024 102 12 0 0 WN
Feb 2024 99 12 1 0 WN
Jan 2024 110 12 0 0 WN

ONT–SJC seasonal on-time pattern

Best: February (91.8%) · weakest: May (83.1%)

82%84%86%88%90%92%94% JanFebMarAprMayJunJulAugSepOctNovDec 85.9%

Strongest calendar month

February

91.8% on-time · ~101 flights/mo

Busiest calendar month

August

~119 flights/mo avg

Weakest calendar month

May

83.1% on-time · ~103 flights/mo

Cancellation Rate

0.2%

5 of 2,701 flights

Diversion Rate

0.0%

0 of 2,701 flights

Origin-hub reliability standing

Among ONT's stronger departures

ONT → SJC posts a 86.8% on-time rate, landing in the ≥85% band with 10 of 21 BTS-tracked routes leaving Ontario. The same hub also shows 9 mid-band and 2 challenged departures · fleet-wide on-time rank #682 of 4927 (highest on-time = #1).

What the Data Says About ONT to SJC

Ontario to San Jose (ONT to SJC) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 86.8% on-time rate across 7,951 flights, with delays that do happen averaging 57.4 minutes. The corridor runs roughly 333 miles and is served by 1 carrier. Over the most recent 24 months, 5 of 2,701 flights were cancelled (0.2%) and 0 diverted (0.0%).

The monthly split is wide on this route: Oct 2024 posted the strongest performance at 97% on-time, while Jul 2025 came in at just 77% - a 20-point swing worth factoring into travel timing.

On the multi-year calendar, ONT–SJC peaks in February at 91.8% on-time while August carries the heaviest traffic (~119 flights per month) ; the softest month is May at 83.1%, a 8.7-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does ONT to SJC rank among US routes by traffic?
According to PlainFlights' route traffic ranking, ONT to SJC ranks #1549 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 ONT to SJC?
Flights from Ontario to San Jose have a 86.8% on-time rate based on 7,951 flights. The average delay is 57.4 minutes. The best recent month was Oct 2024 with 97% on-time.
What is the cancellation rate for ONT to SJC?
Over the last 24 months, 0.2% of flights on this route were cancelled (5 of 2,701 flights) and 0.0% were diverted.
How far is the flight from ONT to SJC?
The flight distance from Ontario (ONT) to San Jose (SJC) is approximately 333 miles. This route is served by 1 carrier.
When is the best time to fly from ONT to SJC?
The best recent month for on-time performance was Oct 2024 (97% on-time). The worst was Jul 2025 (77% on-time). Consider booking during months with historically better performance.

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.

Using ONT–SJC data

ONT–SJC runs 7.8 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare ONT and SJC airport profiles: delay causes and top routes differ even on the same corridor. ONT airport
  • If your dates flex, February (91.8% on-time) beats May (83.1%) on this corridor. Seasonal chart
  • 4 other routes post a similar 86.8% 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.