Flight number record
UA 1833
United Airlines · Boston to Newark
- Route
- BOS → EWR
- Departs
- 06:00
- Flights
- 324
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s UA 1833, check with United Airlines.
UA 1833 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 16 points better than the national rate of 77.3%. When something does go wrong the average delay runs about an hour. That rests on 324 flights, with a median arrival 13 minutes early.
Set against the rest of the country, UA 1833's record is 16 points better than the US average of 77.3%. That gap is worth roughly 155 fewer late arrivals for every thousand flights.
Key figures
On time
92.8%
Arrivals under 15 minutes late, of 319 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
1.54%
National rate is 1.89%
1 hour+ late
2.5%
National rate is 8.3%
These figures cover 324 flights between September 2025 and August 2026. The median arrival is 13 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 1833 flies
UA 1833 flies BOS to EWR without a single fixed slot. Its most common scheduled departure was 06:00, used on 256 of 324 flights, with 06:05 (42 flights) next.
- Departs 06:00256 flights79.0%
- Departs 06:0542 flights13.0%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 1833 runs 4 points better at 92.8%. 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 1833 next to BOS to EWR
Every carrier on BOS to EWR combined arrived on time 75.7% of the time across 3,860 flights, so UA 1833 is 17 points ahead of it. United flew 2,695 flights on the same city pair under all its flight numbers, including this one, and those ran 75.8% on time. Across its whole network United Airlines managed 78.8%, which this flight beats by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1833thin sample | 324 | 92.8% | 63 min | 1.54% | A |
| All United Airlines on BOS–EWR | 2,695 | 75.8% | 88 min | 3.53% | B− |
| All carriers on BOS–EWR | 3,860 | 75.7% | 82 min | 4.51% | B− |
| United Airlines, whole network | 830,825 | 78.8% | 73 min | 1.02% | B |
Across the year
UA 1833 quarter by quarter
UA 1833 did not run the same all year. Its best quarter was Apr–Jun 2026 at 98.8% on time and its weakest Jul–Sep 2026 at 85.7%, a swing of 13 points on roughly 65 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 flights93.3%
- Oct–Dec 202577 flights96.1%
- Jan–Mar 202677 flights87.5%
- Apr–Jun 202684 flights98.8%
- Jul–Sep 202656 flights85.7%
Scale runs 75% to 100%.
By weekday, UA 1833 ranged from 87.5% on Wednesday to 98.0% on Thursday. With about 46 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late UA 1833 runs when it is late
UA 1833 often beats the schedule: 141 of 319 completed flights, 44%, arrived 15 minutes or more early. The 23 late arrivals split 10 under half an hour, 5 between 30 and 60 minutes, and 8 an hour or more.
- 15+ min early141 flights44.2%
- Within 15 min155 flights48.6%
- 15–29 min late10 flights3.1%
- 30–59 min late5 flights1.6%
- 1–2 hours late4 flights1.3%
- 2+ hours late4 flights1.3%
Scale runs 0% to 100%.
Share of 319 completed flights by arrival against schedule.
Only 16 of 319 completed flights left 15 minutes late or more, too few to say how often the time is made up.
The worst days
Worst days for UA 1833
The latest arrival of the period was on 26 September 2025, 3 hours 57 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 26 September 2025 | 3 hours 57 minutes | Carrier |
| 13 December 2025 | 2 hours 58 minutes | Carrier |
| 14 December 2025 | 2 hours 39 minutes | National Airspace System |
| 15 September 2025 | 2 hours 9 minutes | Carrier |
| 29 July 2026 | 1 hour 47 minutes | Carrier |
Delay causes
Why UA 1833 runs late
Carrier accounts for 69% of the 1,443 delay minutes carriers reported here, and the remaining four split what is left.
- 69%Carrier
- 25%National Airspace System
- 6%Extreme weather
The largest share of delay minutes, 69%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 996 of the 1,443 delay minutes reported here. The split is drawn from 1,443 delay minutes reported on UA 1833.
Cancellations sit at 1.54% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 2.5% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The same number turns up on eight other city pairs in the data, including EWR to CLE (96), EWR to EYW (37) and EWR to LAS (36), but none flew often enough under UA 1833 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to EWR only.
One caution: this is a thin sample. 324 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 1833
For a booking, read UA 1833 as 92.8% on time with 1.54% cancelled over 324 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to EWR, every carrier and departure
- EWR to BOS, the return direction
- Republic Airways 5718 on the same route61.1%
- United Airlines 570 on the same route89.4%
- United Airlines 2394 on the same route87.1%
- Boston Logan International (BOS) delay statistics
- Newark Liberty International (EWR) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- The best day of the week to fly, and why it is the second lever
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 ; recomputed monthly. How this data is collected.