Flight number record

UA 1783

United Airlines · Los Angeles to Boston

Route: LAX → BOS
Departs: 08:20
Flights: 365
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1783, check with United Airlines.

UA 1783 lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 365 flights, with a median arrival 11 minutes early.

Set against the rest of the country, UA 1783's record is 5 points better than the US average of 77.3%. That gap is worth roughly 47 fewer late arrivals for every thousand flights.

On time

82.0%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

82 min

Across delayed arrivals only, not all flights

Cancelled

0.82%

National rate is 1.89%

1 hour+ late

7.2%

National rate is 8.3%

These figures cover 365 flights between September 2025 and August 2026. The median arrival is 11 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 1783 flies

UA 1783 flies LAX to BOS without a single fixed slot. Its most common scheduled departure was 08:20, used on 93 of 365 flights, with 08:15 (80 flights) and 08:35 (66 flights) next.

Departs 08:2093 flights25.5%
Departs 08:1580 flights21.9%
Departs 08:3566 flights18.1%

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 08:20 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and UA 1783 runs level with that at 82.0%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

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Against the route

UA 1783 next to LAX to BOS

Every carrier on LAX to BOS combined arrived on time 76.2% of the time across 4,797 flights, so UA 1783 is 6 points ahead of it. United flew 731 flights on the same city pair under all its flight numbers, including this one, and those ran 85.3% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 3 points.

UA 1783 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1783	365	82.0%	82 min	0.82%	B+
All United Airlines on LAX–BOS	731	85.3%	71 min	0.96%	A+
All carriers on LAX–BOS	4,797	76.2%	80 min	1.81%	B
United Airlines, whole network	830,825	78.8%	73 min	1.02%	B

Across the year

UA 1783 quarter by quarter

UA 1783 did not run the same all year. Its best quarter was Jan–Mar 2026 at 92.0% on time and its weakest Jul–Sep 2025 at 60.0%, a swing of 32 points on roughly 73 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 flights60.0%
Oct–Dec 202592 flights81.3%
Jan–Mar 202690 flights92.0%
Apr–Jun 202691 flights86.8%
Jul–Sep 202662 flights72.6%

Scale runs 50% to 95%.

By weekday, UA 1783 did best on Saturday at 92.3% on time and worst on Friday at 76.9%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late UA 1783 runs when it is late

UA 1783 often beats the schedule: 159 of 361 completed flights, 44%, arrived 15 minutes or more early. The 65 late arrivals split 20 under half an hour, 19 between 30 and 60 minutes, and 26 an hour or more.

15+ min early159 flights44.0%
Within 15 min137 flights38.0%
15–29 min late20 flights5.5%
30–59 min late19 flights5.3%
1–2 hours late13 flights3.6%
2+ hours late13 flights3.6%

Scale runs 0% to 100%.

Share of 361 completed flights by arrival against schedule.

Time lost at the gate mostly stays lost. Of 54 departures that left 15 minutes late or more, only 4 made it up before arrival. 15 flights left on time and still arrived late.

The worst days

Worst days for UA 1783

The latest arrival of the period was on 23 March 2026, 6 hours 40 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as national airspace system delay.

The latest arrivals of UA 1783 in the period
Date	Arrived late by	Largest filed cause
23 March 2026	6 hours 40 minutes	Late-arriving aircraft
30 November 2025	5 hours 25 minutes	Late-arriving aircraft
24 September 2025	4 hours 12 minutes	National Airspace System
13 October 2025	3 hours 58 minutes	National Airspace System
25 September 2025	3 hours 53 minutes	National Airspace System

Delay causes

Why UA 1783 runs late

National Airspace System accounts for 65% of the 5,349 delay minutes carriers reported here, and the remaining four split what is left.

National Airspace System
65%
Late-arriving aircraft
27%
Carrier
8%

65% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,500 minutes out of 5,349, against a national NAS share of 21%. The split is drawn from 5,349 delay minutes reported on UA 1783.

Cancellations are rare at 0.82%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

7.2% 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 an hour and a half, which a normal layover absorbs.

At 2,611 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 two other city pairs in the data, including BOS to EWR (33) and BOS to ORD (12), but none flew often enough under UA 1783 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAX to BOS only.

One caution: this is a thin sample. 365 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 1783

For a booking, read UA 1783 as 82.0% on time with 0.82% cancelled over 365 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