Route reliability record
STL→EWR
St. Louis to Newark
- Flights
- 1,075
- Period
- July 2025 to June 2026
- Distance
- 872 mi
- Carriers
- 2
This route carries a cancellation problem, not just a delay problem: 4.6% of scheduled flights never operate, against 1.8% nationally. Of the ones that do fly, about four flights in five arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,075 STL to EWR flights, with a median arrival 13 minutes early.
Best time to fly STL to EWR: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 90.5% of the time and Wednesday flights 84.9%, against 81.3% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
81.3%
Arrivals under 15 minutes late, of 1,023 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
4.56%
National rate is 1.81%
Best carrier
Republic
83.6% on time across 948 flights
These figures cover 1,075 flights between July 2025 and June 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.
Carrier by carrier
Which airline is most reliable on STL to EWR
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 948 | 83.6% | 94 min | 5.17% | B− |
| United Airlinesthin sample | 127 | 65.4% | 91 min | 0.00% | C+ |
Best ways to make this trip
The most reliable ways to fly St. Louis to Newark
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 2 of the top 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. STL → EWRSt. Louis to Newark | Republic Airways | 79.3% | 83.6% | 5.17% | 5am–8am, Fri | — |
| 2. STL → LGASt. Louis to New York | Republic Airways | 76.6% | 80.3% | 4.56% | 8am–11am, Wed | — |
| 3. STL → LGASt. Louis to New York | Southwest Airlines | 68.2% | 70.4% | 3.17% | 5am–8am, Wed | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am379 flights90.5%
- 8am–11am—
- 11am–2pm359 flights81.2%
- 2pm–5pm32 flights77.4%
- 5pm–8pm305 flights70.0%
- 8pm–5am—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.5% of the time, against 70.0% for the evening window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 379 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 33 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
May is the best month on the calendar at 93.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. September was the busiest month here, with 106 flights.
Across the week, Wednesday is the strongest day at 84.9% on time and Sunday the weakest at 76.4%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. National Airspace System accounts for 42% of the 18,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 42%National Airspace System
- 42%Late-arriving aircraft
- 13%Carrier
- 3%Extreme weather
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 18,000 reported delay minutes here, that single category outweighs weather by 13 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 17,890 reported delay minutes.
42% 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 7,591 minutes out of 18,000, against a national NAS share of 21%.
Cancellations run at 4.56%, against 1.81% nationally. That is roughly one flight in twenty 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 stage length
What a delay here actually costs
7.8% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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.
The 872 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 84.6% on time across 1,074 flights, 3 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 3 points of difference.
One caution: this is a thin sample. 1,075 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.
Work out the risk of missing a connection in EWR after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 4.56% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 1,023 completed flights over 12 months sit behind that.
Common questions
STL to EWR questions
How often is STL to EWR delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.7% of the 1,075 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is STL to EWR compared with the rest of the country?
81.3% of flights arrive on time here against a national 77.6%, a difference of 4 points in its favour. That is worth a B− on this site's grading scale.
What time of day has the fewest delays on STL to EWR?
The 5am–8am departure window is the strongest at 90.5% on time. The 5pm–8pm window is the weakest at 70.0%, 21 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are October delays on STL to EWR?
October is the weakest month at 60.4% on time, compared with 93.3% in May. Across the year that is 33 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- EWR to STL — the return legseparate record
- St. Louis Lambert International (STL) delay statistics
- Newark Liberty International (EWR) delay statistics
- Republic Airways on STL to EWR83.6%
- United Airlines on STL to EWR65.4%
- STL to ATL, a related route85.3%
- MCO to EWR, a related route73.8%
- STL to DEN, a related route74.9%
- Republic Airways on-time record83.6%
- United Airlines on-time record65.4%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. STL to EWR and EWR to STL are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.