23 US flights arrived on time exactly zero times in June 2026, the latest month in federal data. Every figure on this page is computed from the Bureau of Transportation Statistics raw flight-level records. Data retrieved August 2026.
The worst on-time flight in America in June 2026 was United 5519 from Carlsbad to San Francisco: it operated 30 times and arrived late all 30, by 17 to 106 minutes. It was one of 23 flights that were never on time once that month, out of 23,279 route-level flights with at least 10 June operations. San Francisco's rough June shows up everywhere - 27 of the 50 worst touch SFO. If your flight is on this list, book with slack and know your fallbacks: the live board for today's reality, Fix My Trip when it goes wrong, and the refund rule a long delay unlocks.
Ranked by the share of June 2026 operations that arrived on time under the DOT standard - within 15 minutes of schedule, with cancellations and diversions counting against. Minimum 10 operations in the month. "Avg delay" covers operations that actually arrived.
| # | Flight | Airline | Route | On time | June ops | Avg delay (min) | 30+ min late or canceled |
|---|---|---|---|---|---|---|---|
| 1 | UA 5519 | United | CLD → SFO | 0.0% | 30 | 58 | 80.0% |
| 2 | WN 4772 | Southwest | SAN → SFO | 0.0% | 23 | 85 | 91.3% |
| 3 | WN 1546 | Southwest | MDW → SFO | 0.0% | 23 | 69 | 87.0% |
| 4 | UA 1757 | United | SFO → RNO | 0.0% | 22 | 61 | 72.7% |
| 5 | WN 673 | Southwest | BNA → SFO | 0.0% | 20 | 78 | 100.0% |
| 6 | UA 6042 | United | GEG → SFO | 0.0% | 17 | 107 | 94.1% |
| 7 | WN 4681 | Southwest | SFO → SAN | 0.0% | 16 | 80 | 93.8% |
| 8 | WN 3476 | Southwest | SAN → AUS | 0.0% | 12 | 119 | 100.0% |
| 9 | WN 3496 | Southwest | SFO → SAN | 0.0% | 12 | 93 | 100.0% |
| 10 | WN 4242 | Southwest | SFO → SAN | 0.0% | 12 | 112 | 100.0% |
| 11 | WN 2343 | Southwest | LAS → SFO | 0.0% | 12 | 66 | 91.7% |
| 12 | WN 2593 | Southwest | AUS → SAN | 0.0% | 12 | 82 | 91.7% |
| 13 | WN 4235 | Southwest | SFO → LAX | 0.0% | 12 | 71 | 91.7% |
| 14 | AS 2219 | Alaska | LAS → SAN | 0.0% | 12 | 76 | 83.3% |
| 15 | WN 1670 | Southwest | DEN → PDX | 0.0% | 12 | 63 | 75.0% |
| 16 | WN 3198 | Southwest | PDX → DEN | 0.0% | 12 | 58 | 75.0% |
| 17 | WN 3208 | Southwest | PHX → AUS | 0.0% | 12 | 53 | 75.0% |
| 18 | WN 3161 | Southwest | LAX → SFO | 0.0% | 12 | 78 | 66.7% |
| 19 | WN 1263 | Southwest | DAL → ATL | 0.0% | 12 | 50 | 50.0% |
| 20 | WN 4368 | Southwest | AUS → OAK | 0.0% | 12 | 36 | 41.7% |
| 21 | WN 3667 | Southwest | SJC → DEN | 0.0% | 12 | 30 | 25.0% |
| 22 | WN 3241 | Southwest | PHX → BOI | 0.0% | 11 | 64 | 72.7% |
| 23 | AS 3299 | Alaska | SFO → RDM | 0.0% | 11 | 50 | 63.6% |
| 24 | AA 2117 | American | DFW → MCO | 3.3% | 30 | 90 | 83.3% |
| 25 | UA 5423 | United | SUN → SFO | 3.3% | 30 | 54 | 80.0% |
| 26 | WN 136 | Southwest | DEN → SMF | 3.7% | 27 | 72 | 92.6% |
| 27 | WN 2217 | Southwest | DEN → LAX | 3.7% | 27 | 63 | 70.4% |
| 28 | WN 2557 | Southwest | RIC → DEN | 3.7% | 27 | 58 | 66.7% |
| 29 | WN 1101 | Southwest | BWI → SFO | 4.3% | 23 | 66 | 87.0% |
| 30 | WN 3652 | Southwest | SFO → SAN | 4.3% | 23 | 61 | 78.3% |
| 31 | WN 2521 | Southwest | PHX → MDW | 4.3% | 23 | 57 | 73.9% |
| 32 | WN 2686 | Southwest | DEN → PHL | 4.3% | 23 | 44 | 47.8% |
| 33 | AS 3075 | Alaska | SFO → GEG | 4.8% | 21 | 74 | 90.5% |
| 34 | AS 3202 | Alaska | GEG → PDX | 4.8% | 21 | 68 | 90.5% |
| 35 | AA 2117 | American | MCO → DFW | 4.8% | 21 | 95 | 85.7% |
| 36 | AA 2319 | American | DFW → PHX | 4.8% | 21 | 71 | 81.0% |
| 37 | WN 3641 | Southwest | SFO → DEN | 5.0% | 20 | 73 | 90.0% |
| 38 | WN 1288 | Southwest | LAS → SAN | 5.0% | 20 | 69 | 70.0% |
| 39 | WN 3633 | Southwest | SFO → AUS | 5.3% | 19 | 61 | 94.7% |
| 40 | UA 2861 | United | CMH → SFO | 5.6% | 18 | 94 | 88.9% |
| 41 | WN 2429 | Southwest | LAX → SFO | 6.2% | 16 | 89 | 93.8% |
| 42 | WN 4392 | Southwest | AUS → HOU | 6.2% | 16 | 60 | 81.2% |
| 43 | UA 2384 | United | DFW → SFO | 6.2% | 16 | 50 | 75.0% |
| 44 | F9 2677 | Frontier | ONT → SFO | 6.7% | 30 | 73 | 83.3% |
| 45 | UA 1508 | United | BUR → SFO | 6.7% | 30 | 79 | 76.7% |
| 46 | AS 3226 | Alaska | RDM → SFO | 7.1% | 14 | 79 | 85.7% |
| 47 | AS 3237 | Alaska | SFO → SNA | 7.7% | 13 | 42 | 46.2% |
| 48 | WN 63 | Southwest | DAL → HOU | 7.7% | 13 | 57 | 38.5% |
| 49 | UA 2854 | United | BUR → SFO | 8.3% | 24 | 59 | 83.3% |
| 50 | WN 1454 | Southwest | SAN → LAS | 8.3% | 12 | 53 | 91.7% |
Flights sold under a major airline's number but flown by a regional partner are marked by the seller here, matching how they are sold: rank 1 is United Express flown by SkyWest, and several Alaska rows are Horizon or SkyWest operations. Ties are broken by more operations, then by the worse severe-delay share.
This is a one-month snapshot by design, the same way the DOT used to publish its chronically delayed flight lists. June 2026 was a rough month at San Francisco, and that dominates the table; a January list would look like a winter list. A flight number can also be retimed or rescheduled between months. So read it as a warning light: if a flight you are considering is here, check its recent record before betting a tight connection on it.
The streaks matter more than any single month. In June, 869 route-level flights met the chronic-delay test (more than half of operations 30+ minutes late or canceled); 76 had met it two months running, and one - Frontier 3288 from Atlanta to LaGuardia - had met it four consecutive months, March through June.
A chronically late flight is not a reason to panic; it is a reason to plan. Do not book it as the first leg of a tight same-day connection. Check the live airport board before you leave for the airport. If the delay reaches three hours domestic, the DOT refund rule lets you take your money back instead of flying. And if it strands you, Fix My Trip finds every way home across airlines and nearby airports, and Know Your Rights covers what the airline owes you along the way.
Source: BTS TranStats, "Marketing Carrier On-Time Performance (Beginning January 2018)", June 2026 monthly extract (671,781 scheduled-flight records), with January through May 2026 used for streak counts. Flights are grouped by marketing carrier, flight number, origin, and destination; segments with fewer than 10 June operations are excluded (DOT's own floor for chronic-delay evaluation), leaving 23,279 qualified segments. On time means arrival less than 15 minutes after the scheduled CRS time - the DOT standard - and canceled or diverted operations count as not on time. Average delay is the mean over operations that arrived, so early arrivals count negative and heavily canceled flights can look milder than they felt. The pipeline was validated by recomputing May 2026 network on-time rates and matching them against DOT's published Air Travel Consumer Report carrier table.
The modern Air Travel Consumer Report no longer lists individual flights; it points readers to this same BTS database, which is what TripHero computes from. General guidance, not booking advice for any specific date. Found an error? Tell us and we will fix it.
Related: Delayed 3 hours - refund? · Know your rights · Today's Disruption Index · Glossary