Flight number record

UA 427

United Airlines · San Diego to Newark

Route: SAN → EWR
Departs: 22:30
Flights: 363
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s UA 427, check with United Airlines.

UA 427 lands a B, 4 points better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 363 flights, with a median arrival 9 minutes early.

Set against the rest of the country, UA 427's record is 4 points better than the US average of 77.3%. That gap is worth roughly 43 fewer late arrivals for every thousand flights.

On time

81.6%

Arrivals under 15 minutes late, of 354 completed flights

Avg delay

63 min

Across delayed arrivals only, not all flights

Cancelled

1.93%

National rate is 1.89%

1 hour+ late

5.6%

National rate is 8.3%

These figures cover 363 flights between September 2025 and August 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

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Schedule

When UA 427 flies

UA 427 flies SAN to EWR without a single fixed slot. Its most common scheduled departure was 22:30, used on 93 of 363 flights, with 13:35 (37 flights) next.

Departs 22:3093 flights25.6%
Departs 13:3537 flights10.2%

Scale runs 0% to 100%.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 22:30 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and UA 427 runs 12 points better at 81.6%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

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Against the route

UA 427 next to SAN to EWR

Every carrier on SAN to EWR combined arrived on time 81.9% of the time across 1,557 flights, so UA 427 is about level with it. United flew 1,229 flights on the same city pair under all its flight numbers, including this one, and those ran 81.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 3 points.

UA 427 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 427thin sample	363	81.6%	63 min	1.93%	B
All United Airlines on SAN–EWR	1,229	81.3%	92 min	2.12%	B
All carriers on SAN–EWR	1,557	81.9%	90 min	2.25%	B
United Airlines, whole network	830,825	78.8%	73 min	1.02%	B

Across the year

UA 427 quarter by quarter

UA 427 did not run the same all year. Its best quarter was Apr–Jun 2026 at 93.4% on time and its weakest Jul–Sep 2026 at 71.7%, a swing of 22 points on roughly 91 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202530 flights—
Oct–Dec 202592 flights80.0%
Jan–Mar 202689 flights76.2%
Apr–Jun 202691 flights93.4%
Jul–Sep 202661 flights71.7%

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 427 did best on Friday at 88.2% on time and worst on Thursday at 71.2%. Each day rests on about 52 flights, so a gap of 17 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late UA 427 runs when it is late

UA 427 often beats the schedule: 134 of 354 completed flights, 38%, arrived 15 minutes or more early. The 65 late arrivals split 25 under half an hour, 20 between 30 and 60 minutes, and 20 an hour or more.

15+ min early134 flights37.9%
Within 15 min155 flights43.8%
15–29 min late25 flights7.1%
30–59 min late20 flights5.6%
1–2 hours late14 flights4.0%
2+ hours late6 flights1.7%

Scale runs 0% to 100%.

Share of 354 completed flights by arrival against schedule.

13 of 54 late departures made up the time and arrived on time, 24% of them. In the other direction, 24 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at EWR.

The worst days

Worst days for UA 427

The latest arrival of the period was on 11 March 2026, 11 hours 59 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across March, July, January, December and September, with no single month standing out.

The latest arrivals of UA 427 in the period
Date	Arrived late by	Largest filed cause
11 March 2026	11 hours 59 minutes	Extreme weather
26 July 2026	3 hours 6 minutes	Carrier
17 January 2026	2 hours 50 minutes	Late-arriving aircraft
9 December 2025	2 hours 35 minutes	Late-arriving aircraft
4 September 2025	2 hours 26 minutes	National Airspace System

Delay causes

Why UA 427 runs late

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 4,069 reported delay minutes.

National Airspace System
39%
Late-arriving aircraft
23%
Carrier
19%
Extreme weather
18%

Extreme weather accounts for 18% 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 quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.0 times the usual weather exposure. The split is drawn from 4,069 delay minutes reported on UA 427.

Cancellations sit at 1.93% against a national 1.89%, which is ordinary. Diversions add another 0.55%.

Connections and routes

What a delay on this flight costs

5.6% of arrivals land an hour or more late, close to the national 8.3%, so 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.

At 2,425 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The same number turns up on one other city pair in the data, including DEN to XNA (1), but none flew often enough under UA 427 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SAN to EWR only.

One caution: this is a thin sample. 363 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking UA 427

For a booking, read UA 427 as 81.6% on time with 1.93% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures