Flight number record
YX 5619
Republic Airways · Boston to Milwaukee
- Route
- BOS → MKE
- Departs
- 20:45
- Flights
- 292
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s YX 5619, check with Republic Airways. Republic Airways flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
YX 5619 lands a B−, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 292 flights, with a median arrival 6 minutes early.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 273 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
6.16%
National rate is 1.89%
1 hour+ late
8.4%
National rate is 8.3%
These figures cover 292 flights between September 2025 and August 2026. Beyond the headline rate, 8.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When YX 5619 flies
YX 5619 flies BOS to MKE without a single fixed slot. Its most common scheduled departure was 20:45, used on 49 of 292 flights, with 16:25 (45 flights) and 16:50 (31 flights) next.
- Departs 20:4549 flights16.8%
- Departs 16:2545 flights15.4%
- Departs 16:5031 flights10.6%
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 20:45 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and YX 5619 runs 7 points better at 76.9%. 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
YX 5619 next to BOS to MKE
Every carrier on BOS to MKE combined arrived on time 82.7% of the time across 737 flights, so YX 5619 is 6 points behind it. Republic flew 540 flights on the same city pair under all its flight numbers, including this one, and those ran 82.2% on time. Across its whole network Republic Airways managed 78.1%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| YX 5619thin sample | 292 | 76.9% | 57 min | 6.16% | B− |
| All Republic Airways on BOS–MKE | 540 | 82.2% | 54 min | 4.26% | B− |
| All carriers on BOS–MKE | 737 | 82.7% | 58 min | 3.53% | B− |
| Republic Airways, whole network | 364,452 | 78.1% | 74 min | 4.55% | B− |
Across the year
YX 5619 quarter by quarter
YX 5619 did not run the same all year. Its best quarter was Jan–Mar 2026 at 85.5% on time and its weakest Oct–Dec 2025 at 69.6%, a swing of 16 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 202526 flights—
- Oct–Dec 202552 flights69.6%
- Jan–Mar 202683 flights85.5%
- Apr–Jun 202678 flights82.9%
- Jul–Sep 202653 flights77.6%
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, YX 5619 ranged from 72.7% on Tuesday to 82.6% on Wednesday. With about 42 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late YX 5619 runs when it is late
YX 5619 often beats the schedule: 98 of 273 completed flights, 36%, arrived 15 minutes or more early. The 63 late arrivals split 20 under half an hour, 20 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early98 flights35.9%
- Within 15 min112 flights41.0%
- 15–29 min late20 flights7.3%
- 30–59 min late20 flights7.3%
- 1–2 hours late18 flights6.6%
- 2+ hours late5 flights1.8%
Scale runs 0% to 100%.
Share of 273 completed flights by arrival against schedule.
18 of 75 late departures made up the time and arrived on time, 24% of them. 6 flights left on time and still arrived late.
The worst days
Worst days for YX 5619
The latest arrival of the period was on 11 March 2026, 3 hours 30 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across March, July, May, September and April, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 March 2026 | 3 hours 30 minutes | National Airspace System |
| 6 July 2026 | 3 hours 18 minutes | Late-arriving aircraft |
| 19 May 2026 | 3 hours 6 minutes | National Airspace System |
| 12 September 2025 | 2 hours 36 minutes | Carrier |
| 10 April 2026 | 2 hours 6 minutes | Carrier |
Delay causes
Why YX 5619 runs late
Late-arriving aircraft accounts for 52% of the 3,604 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 24%Carrier
- 22%National Airspace System
- 2%Extreme weather
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,604 reported delay minutes here, that single category outweighs weather by 24 to one. The split is drawn from 3,604 delay minutes reported on YX 5619.
Cancellations run at 6.16%, against 1.89% nationally. That is roughly one flight in fifteen cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
8.4% 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.
The 860 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The same number turns up on five other city pairs in the data, including MKE to BOS (229), JFK to IND (11) and GSO to LGA (5), but none flew often enough under YX 5619 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to MKE only.
One caution: this is a thin sample. 292 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 YX 5619
For a booking, the cancellation rate is the figure to plan around on YX 5619: 6.16% of its 292 scheduled flights did not operate. A late arrival costs about an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- BOS to MKE, every carrier and departure
- MKE to BOS, the return direction
- Boston Logan International (BOS) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- Republic Airways on-time record
- Every Republic Airways flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Republic Airways’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.