United Airline Operations Outlook
Validated report generated 2026-08-18 16:53 UTC
|
14-day outlook
Expected systemwide on-time performance and primary modeled airport impacts. A14 and A60 values are percentages.
| Date |
Systemwide A14 / A60 |
Impacted airports and timing |
| 2026-08-18 |
A14 77.7% / A60 90.2% |
BOS — low ceilings, 1300-2200 EDT; ground stop 1702-1830Z; A14 78.0% / A60 88.2%
ORD — thunderstorms, 1400-0000 CDT; A14 66.2% / A60 81.9%
SFO — low ceilings, GDP 0830-1300 PDT; capacity risk through late afternoon; A14 80.6% / A60 93.9% |
| 2026-08-19 |
A14 81.3% / A60 92.2% |
DEN — thunderstorms, 1100-2000 MDT; A14 78.1% / A60 89.0%
SFO — low ceilings, 0700-1600 PDT with residual evening constraints; A14 75.3% / A60 87.1% |
| 2026-08-20 |
A14 76.1% / A60 88.7% |
BOS — thunderstorms, 1200-2200 EDT; A14 69.0% / A60 81.4%
DCA — thunderstorms, 1200-2300 EDT; A14 65.4% / A60 80.0%
EWR — thunderstorms, 1300-0100 EDT; A14 60.7% / A60 81.5%
IAD — thunderstorms, 1200-1900 EDT; A14 61.1% / A60 79.8%
LGA — thunderstorms, 1200-0000 EDT; A14 64.6% / A60 80.7%
SFO — low ceilings, 0900-1500 PDT; A14 59.9% / A60 76.6% |
| 2026-08-21 |
A14 76.4% / A60 89.5% |
ATL — thunderstorms, 1600-2200 EDT; A14 60.2% / A60 78.1%
DCA — thunderstorms, 1300-2100 EDT; A14 67.6% / A60 82.1%
EWR — thunderstorms, 1200-2200 EDT; A14 69.9% / A60 88.6%
SFO — low ceilings, 1100-1300 PDT; A14 67.9% / A60 81.1% |
| 2026-08-22 |
A14 76.6% / A60 90.4% |
BOS — low ceilings, 1100-1800 EDT; thunderstorms after 1800; A14 67.4% / A60 80.4%
EWR — thunderstorms, 1200-2200 EDT; A14 62.5% / A60 81.2% |
| 2026-08-23 |
A14 75.4% / A60 88.0% |
BOS — thunderstorms, 1100-0000 EDT; A14 65.9% / A60 80.3%
EWR — thunderstorms, 1300-0000 EDT; A14 57.1% / A60 72.1%
LGA — thunderstorms, 0800-2300 EDT; A14 59.3% / A60 77.9% |
| 2026-08-24 |
A14 80.3% / A60 91.9% |
BOS — thunderstorms, 0800-2200 EDT; A14 71.2% / A60 87.3%
SFO — timing 0900 PDT through late evening; A14 70.7% / A60 82.4% |
| 2026-08-25 |
A14 83.2% / A60 92.7% |
DCA — thunderstorms, 1600-2100 EDT with recovery constraints after; A14 75.5% / A60 85.4%
LGA — thunderstorms, 1400-2200 EDT; A14 73.3% / A60 86.9% |
| 2026-08-26 |
A14 76.1% / A60 87.8% |
No airport-specific impacts in the systemwide summary. |
| 2026-08-27 |
A14 73.0% / A60 87.1% |
BOS — low ceilings, 1300-1900 EDT; A14 59.6% / A60 76.5%
DCA — thunderstorms, 1300-2100 EDT; A14 58.3% / A60 73.6%
EWR — thunderstorms, 1100-2200 EDT; A14 47.4% / A60 69.4%
SFO — timing 0600 PDT through late evening; A14 63.7% / A60 79.5% |
| 2026-08-28 |
A14 81.3% / A60 92.6% |
BOS — low ceilings, 1500-2100 EDT; A14 73.9% / A60 86.4%
DFW — thunderstorms, 0700-0800 CDT; A14 75.9% / A60 90.0%
SFO — timing 0700 PDT through late evening; A14 70.9% / A60 83.5% |
| 2026-08-29 |
A14 85.3% / A60 94.9% |
BOS — low ceilings, 1500-1900 EDT; A14 79.6% / A60 89.5%
SFO — timing 0700-1900 PDT; A14 84.5% / A60 94.0% |
| 2026-08-30 |
A14 84.4% / A60 94.3% |
SFO — timing 0700 PDT through late evening; A14 76.9% / A60 88.3% |
| 2026-08-31 |
A14 81.6% / A60 92.1% |
BOS — low ceilings 1100-1500 EDT; thunderstorms 1500-1900; A14 80.1% / A60 90.6%
MCO — thunderstorms, 1400-1800 EDT with arrival constraints into midnight; A14 65.8% / A60 78.7%
SFO — timing 0800 PDT through late evening; A14 73.7% / A60 86.9% |
|
Airport-date findings
|
2026-08-18
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | FAA validation reports a BOS/ZBW ground stop for low ceilings from 1702Z-1830Z, medium extension probability, and arrival rate 38; this supersedes the earlier no-event report. TMI probability reaches 87.7% at 22Z; arrival-constraint probability reaches 77.2% at 21Z, with scenarios as low as 24 arrivals/hour. Visibility deteriorates overnight to 0.5 miles and an 800-foot overcast is forecast from 06Z. | 17Z-02Z; 03Z-07Z recovery risk | Immediate ground-stop exposure and evening constraints may delay inbound and outbound rotations. Protect overnight aircraft and crew recovery. |
| ORD | FAA validation confirms ORD/MDW ground-stop or delay-program planning after 1900Z, although no active ORD event was returned. Thunderstorm-labeled arrival constraints peak at 94.8% at 00Z; TMI probability peaks at 60.9% at 02Z. Median rates are near 66/hour, with adverse scenarios as low as 28/hour. | 19Z-05Z; strongest 22Z-03Z | Evening bank exposure across 636 UA flights; plan for holding, missed connections, diversions, and crew/aircraft displacement. |
| SFO | FAA validation confirms an active low-ceiling GDP from 1530Z-1959Z covering contiguous-U.S. departures, with average delay 42 minutes, maximum delay 89 minutes, and arrival rate 36. Arrival constraints are near certain from 19Z-22Z; TMI likelihood is 100% at 16Z-17Z. | 1530Z-1959Z GDP; 19Z-22Z; 23Z-04Z | Immediate network issue for 248 UA flights. Manage GDP compliance, protect transcontinental connections, and expect late aircraft displacement. |
|
2026-08-19
| Airport | Key findings | Affected hours | Operational impact |
|---|
| DEN | Low-visibility-labeled TMI risk is about 60% from 14Z-16Z, followed by thunderstorm-labeled risk from 17Z-01Z. Arrival constraints rise to 57.6% at 00Z; lower-tail rates are 46-57/hour. FAA planning indicates possible DEN ground stop/delay program and arrival-route restrictions. | 14Z-16Z; 17Z-02Z; 02Z-05Z recovery | Prolonged event affecting 547 UA flights; substantial connection-bank and crew-duty risk, including carryover from prior-day disruption. |
| SFO | Low-ceiling TMI likelihood peaks at 90.4% at 17Z and remains elevated into evening; restrictive rates are likely 32-36. Arrival constraints reach 78.2% at 21Z, with likely rates near 28-32/hour. | 14Z-23Z; 00Z-05Z | Prior-day GDP creates carryover potential across most of the 271-flight operation. Avoid tight turns and preserve late-evening recovery aircraft. |
|
2026-08-20
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Thunderstorm-labeled arrival constraints peak at 73.4% at 21Z; lower-tail rates are 24-29/hour. TMI scenarios include 38-rate operations from 16Z-02Z and a temporary 26-rate outcome. | 16Z-02Z; 03Z-07Z recovery | Evening disruption may be difficult to recover; expect arrival metering and late aircraft/crew effects into the next BOS day. |
| DCA | Thunderstorm-labeled TMI probability peaks at 60.2% at 21Z; arrival constraints peak at 86.9% at 01Z. Likely rates are 20-24/hour during the core period. | 16Z-03Z; strongest 00Z-04Z | Curfew-sensitive operation has little recovery margin. Protect late arrivals and crews against overnight spillover. |
| EWR | Thunderstorm-labeled TMI probability peaks at 56.5% at 22Z and remains material through 05Z. Arrival risk remains 28-40%, with adverse rates of 23-30/hour. | 17Z-23Z; 00Z-05Z | The 385-flight operation may accumulate substantial delay without a formal GDP. Monitor connections, gates, and crew legality overnight. |
| IAD | Thunderstorm-labeled TMI probability reaches 73.3% at 19Z; arrival constraints peak at 65.0% at 21Z. Adverse arrival scenarios reach 29/hour. | 15Z-23Z; 23Z-06Z recovery | The 268-flight bank is vulnerable to holding, diversions, and onward crew/aircraft mispositioning. |
| LGA | Thunderstorm-labeled TMI probability peaks at 57.2% at 22Z; arrival constraints peak at 62.8% at 01Z. Likely rates fall near 27-33/hour. | 16Z-04Z; highest 22Z-03Z | Late peak and slot constraints limit recovery and may propagate delays across East Coast rotations. |
| SFO | Low-ceiling-labeled TMI probability peaks at 91.3% at 17Z and remains elevated through 05Z. Arrival constraints peak at 77.1% at 01Z; downside scenarios hold arrivals at 28/hour. | 16Z-22Z; 23Z-05Z | Persistent throttling threatens gate, crew, and aircraft rotations across 306 UA flights. |
|
2026-08-21
| Airport | Key findings | Affected hours | Operational impact |
|---|
| ATL | Thunderstorm-labeled TMI probability peaks at 82.9% at 01Z; arrival constraints peak at 65.3% at 22Z. Scenarios include 30-rate periods. | 19Z-02Z; 02Z-04Z recovery | Concentrated evening event may disrupt feeder and mainline flows and next-day repositioning. |
| DCA | Thunderstorm-labeled TMI probability peaks at 52.1%; arrival constraints peak at 92.4% at 00Z and exceed 75% from 18Z-03Z. | 17Z-02Z; 03Z-07Z | Overnight peak is severe for a slot- and curfew-constrained airport. Plan passenger reaccommodation and recovery. |
| EWR | Thunderstorm-labeled TMI probability peaks at 77.4% at 21Z; arrival constraints peak at 56.6% at 00Z. Higher-probability TMI scenario applies a 24 rate from 18Z-22Z. | 16Z-02Z; 23Z-02Z | High-volume exposure can amplify disruption. Preserve late-evening crew and aircraft recovery buffers. |
| SFO | TMI probability peaks at 86.1%; arrival constraints peak at 72.8% at 01Z. Low ceilings are explicit from 18Z-20Z; likely rates are 32-36 and arrivals near 28/hour. | 13Z-05Z; 18Z-20Z; 00Z-02Z | Restriction spans nearly the full productive day for 307 UA flights. Protect aircraft turns and crews. |
|
2026-08-22
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Low-ceiling-labeled TMI probability peaks at 83.0% at 20Z; the condition changes to thunderstorms from 22Z-01Z. Arrival constraints peak at 73.3% at 21Z, with lower-tail rates near 24-29/hour. | 15Z-22Z; 22Z-02Z; 02Z-07Z | Evening peak and overnight recovery require protected aircraft rotations and crews. |
| EWR | Thunderstorm-labeled TMI probability peaks at 67.9% at 20Z and remains elevated through 02Z. Arrival risk is 29-40%, with median rates near 27 and lower-tail outcomes near 23/hour. | 15Z-19Z; 20Z-02Z | Event overlaps the core arrival period; metering and reroutes may delay aircraft and crew sequences into the following morning. |
|
2026-08-23
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Low ceilings are labeled at 14Z, followed by thunderstorms from 15Z-04Z; TMI probability peaks at 80.6% at 19Z. Arrival constraints peak at 72.2% at 04Z, with median rates near 29-32/hour. | 15Z-01Z; 02Z-04Z; 05Z-07Z | Late-running event creates crew-timeout and overnight aircraft-position risk. |
| CMH | No TMI, GDP, arrival-constraint record, or scenario was returned. Visibility is 15 miles; no precipitation or thunderstorms are indicated. | None reported | No airport-specific capacity disruption is modeled; minor wind variability should be recoverable. |
| EWR | Thunderstorm-labeled TMI probability peaks at 44.9% at 19Z; arrival constraints peak at 47.8% at 01Z. Scenarios include 24-36 rates during afternoon/evening or overnight. | 17Z-04Z; highest 21Z-04Z | Moderate risk across 379 UA flights; maintain overnight recovery capacity. |
| IND | No TMI, GDP, arrival-constraint record, or airport scenario was returned. Forecast is broadly favorable. | None reported | No airport-driven disruption is indicated. |
| LGA | Thunderstorm-labeled TMI scenarios include a 64.6% probability of a 28-rate period from 13Z-20Z; arrival scenarios reduce rates to 21-37/hour and may continue through 03Z. | 12Z-20Z; 17Z-03Z | Broad daytime restriction may impair later turns; late constraint tail limits recovery. |
| SFO | TMI probability peaks at 86.2% at 02Z; arrival constraints peak at 84.3% at 00Z-01Z. Downside scenarios sustain 28 arrivals/hour from 17Z-06Z despite favorable weather. | 14Z-18Z; 19Z-05Z | High-capacity-risk day for 309 UA flights; manage late-day aircraft and crew recovery. |
|
2026-08-24
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Thunderstorm-labeled TMI probability rises to 96.4% at 21Z and remains above 81% through 00Z. Arrival constraints reach 60.7% at 21Z; adverse scenarios include 34-36 rates. | 12Z-17Z; 17Z-02Z; 02Z-04Z | High-confidence afternoon/evening restriction. Build delay and crew-duty contingencies before the peak. |
| SFO | TMI probability peaks at 90.3% at 17Z; arrival constraints peak at 72.4% at 23Z. Low ceilings are explicit from 16Z-21Z; scenarios support 28 arrivals/hour through 05Z. | 16Z-21Z; 22Z-05Z | Long restriction can cascade through the 304-flight operation. Protect evening connections and overnight recovery. |
|
2026-08-25
| Airport | Key findings | Affected hours | Operational impact |
|---|
| DCA | Thunderstorm-labeled TMI risk is concentrated from 20Z-01Z; arrival constraints peak at 82.2% at 00Z. Scenarios reduce capacity to 20-30/hour from 20Z-04Z. | 18Z-04Z; 20Z-01Z; 01Z-05Z | Late arrival-capacity event may cause substantial schedule displacement with limited overnight recovery. |
| LGA | Thunderstorm-labeled TMI probability peaks at 44.1% at 00Z; arrival constraints peak at 54.8% at 19Z. Combined probability of reduced late-evening/overnight rates is about 57.9%. | 15Z-18Z; 18Z-03Z | Material evening-peak risk. Hold contingency gate and crew buffers into the overnight. |
|
2026-08-26
| Airport | Key findings | Affected hours | Operational impact |
|---|
| IND | No modeled TMI, GDP, or arrival-capacity constraint was returned. Visibility remains 15 miles; no thunderstorms are forecast. Northwest winds may gust up to 29 knots late. | 18Z-06Z wind exposure; 00Z possible trace precipitation | Modest spacing, taxi, or turn-time variability is possible; no airport capacity disruption is modeled. |
|
2026-08-27
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Low ceilings are explicit from 17Z-23Z, when TMI probability peaks at 29.2%. Arrival constraints peak at 62.6% at 02Z; median rates are 32-35/hour. | 17Z-23Z; 00Z-06Z | Late arrival-recovery threat may require overnight holding and aircraft/crew displacement planning. |
| CLE | No TMI or GDP record/scenario was returned. Arrival constraints peak at 33.2% at 04Z, with low-tail rates near 7-10/hour. No thunderstorms are indicated. | 02Z-05Z | Limited late-night exposure affecting a small number of arrivals; unlikely to be systemwide. |
| DCA | Thunderstorm-labeled TMI probability rises to 35.3% at 23Z; arrival constraints peak at 87.0% at 01Z. Arrival scenarios include 20-33 rates from 18Z-02Z. | 17Z-02Z; 02Z-05Z | Very high overnight arrival risk may create late diversions, cancellations, and next-day recovery issues. |
| EWR | Thunderstorm-labeled TMI probability peaks at 61.1% at 21Z; arrival constraints peak at 62.0% at 01Z. Scenarios include 23-rate outcomes at 03Z-04Z. | 15Z-02Z; 00Z-05Z | Principal network risk; late restrictions may cascade into crew legality, gate congestion, and next-morning aircraft availability. |
| LGA | Arrival constraints peak at 63.3% at 00Z, with median rates near 27-33/hour. Hourly TMI probability is relatively low at 12-15%; no primary condition label was returned. | 18Z-02Z; 03Z-07Z | Arrival-capacity, rather than formal-TMI, risk may still impair late recovery in a slot-constrained operation. |
| SFO | TMI probability reaches 90.5% at 17Z and remains above 73% through 04Z; arrival constraints peak near 79.1% at 01Z. Scenarios support 28 arrivals/hour from 17Z-05Z. | 13Z-06Z; strongest 23Z-02Z | Prolonged capacity pressure across 307 UA flights; preserve recovery buffers into the night. |
|
2026-08-28
| Airport | Key findings | Affected hours | Operational impact |
|---|
| ATL | Arrival constraints peak at 55.1% at 22Z; TMI probability remains below 6.6%. No named condition is supplied; adverse arrival scenario reduces capacity to 80% at 23Z. | 19Z-01Z | Monitor evening arrivals; forecast supports a recoverable, limited event. |
| BOS | Low ceilings are labeled from 19Z-00Z. Arrival constraints peak at 51.3% at 21Z; TMI probability peaks at 35.7% at 20Z. | 19Z-01Z; 01Z-04Z | Moderate evening sequencing risk may extend recovery into late-night BOS turns. |
| DFW | Thunderstorm-labeled TMI probability is 22-25% at 12Z-13Z. Arrival constraints peak at 87.7% at 02Z; lower-tail rates fall to 45-57/hour overnight. | 12Z-13Z; 23Z-04Z | Early signal is likely recoverable; overnight capacity risk may delay late arrivals and rotations. |
| LAS | Arrival constraints peak at 70.0% at 22Z; TMI probability remains below 11%. Arrival scenarios include 35-50 rates in the evening and overnight. | 20Z-02Z; 02Z-05Z | Moderate risk for 46 UA flights; wind and heat may reduce flexibility, but systemwide effects should remain limited. |
| LGA | Arrival constraints are 98.6-100% from 13Z-17Z and 97.3% at 18Z, with median rates near 21-27/hour. Hourly TMI probability is zero; no named condition is supplied. | 11Z-12Z; 13Z-18Z; 18Z-02Z | Severe modeled arrival-capacity day despite benign surface weather; manage as a major LGA flow problem. |
| PHX | No hourly TMI is modeled. Arrival constraints peak at 37.3% at 02Z; median rates are near 57, with isolated 50-rate periods. Temperatures reach about 106F. | 19Z-05Z; highest 01Z-05Z | Heat and wind shifts may reduce margin, but no broad capacity event is modeled. |
| SAN | TMI probability is about 20-25% through 03Z. No airport arrival-capacity constraint was returned; scenarios favor 35/hour with a 20.5% 24-rate outcome. | 11Z-03Z; peak 17Z-19Z | Effects should be demand-management related and contained; monitor upstream delay propagation. |
| SFO | TMI probability peaks at 84.1% at 17Z; arrival constraints peak at 74.9% at 01Z. Downside scenarios sustain 28 arrivals/hour from 15Z-06Z; gusts reach 15-28 knots. | 16Z-22Z; 23Z-04Z | High-volume evening risk; protect delayed aircraft, crews, and connection flows. |
|
2026-08-29
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Low ceilings are labeled from 19Z-23Z; TMI probability peaks at 26.2% at 21Z. Arrival constraints peak at 53.2% at 03Z, with median rates near 32-35/hour. | 19Z-23Z; 00Z-04Z | Moderate evening disruption may become a late overnight recovery issue; monitor final arrivals and next-day positioning. |
| SEA | No hourly TMI is modeled. Arrival constraints climb overnight to 52.4% at 04Z; some scenarios reduce rates to 45-56 near 02Z-05Z. | 02Z-06Z | Localized overnight arrival-flow risk may delay late West Coast rotations. |
| SFO | TMI probability peaks at 84.4% at 17Z; arrival constraints peak at 85.3% at 20Z. Dominant scenario holds arrivals at 28/hour from 18Z-01Z; gusts reach 34-35 knots. | 14Z-23Z; 16Z-02Z; 18Z-01Z | Strong wind and sustained low-rate scenario create major evening risk: holding, metering, gate compression, and crew/aircraft displacement. |
|
2026-08-30
| Airport | Key findings | Affected hours | Operational impact |
|---|
| SFO | Arrival constraints peak at 83.1% at 01Z; TMI probability peaks at 87.1% at 02Z. Most likely scenario holds a 28 rate from 18Z-06Z; TMI scenarios frequently use 32-36 rates. | 14Z-05Z; core 17Z-04Z | Long evening/overnight restriction may materially affect 306 UA flights. Hold crew and aircraft recovery capacity. |
|
2026-08-31
| Airport | Key findings | Affected hours | Operational impact |
|---|
| BOS | Low ceilings are labeled from 15Z-18Z and thunderstorms from 19Z-23Z. Adverse TMI scenario has repeated 38-rate periods. Arrival constraints rise to 48.5% at 02Z. | 15Z-18Z; 19Z-23Z; 00Z-03Z | Moderate but late event creates recovery and crew-positioning risk. |
| MCO | Thunderstorm-labeled TMI probability peaks at 34.2% at 20Z; arrival constraints peak at 68.1% at 23Z-00Z. Adverse scenario reduces rates to 26-35 from 21Z-01Z. | 18Z-22Z; 21Z-03Z | Evening convection can delay 37 UA flights and carry into late-night recovery. Prioritize inbound connections and crew protection. |
| SFO | TMI probability peaks at 92.6% at 17Z; arrival constraints peak at 79.8% at 20Z-21Z. Highest-probability scenario holds a 28 rate from 17Z-05Z; gusts reach 24-26 knots. | 16Z-18Z; 19Z-04Z; 05Z-08Z | High-likelihood, long-duration capacity event across 305 UA flights. Protect next-day aircraft and crew availability. |
|
Waiver information
| Title | United waiver: Chicago Thunderstorms |
| Scope | ORD; UA; arrivals and departures; domestic and international |
| Eligibility | Original travel date 2026-08-15; ticket booked on or before 2026-08-13; new travel on or before 2026-08-18; UA/016 ticket stock |
| Waiver code | 7JCU6 |
| Outlook status | Not applicable to travel after 2026-08-18; do not use for the forward ORD thunderstorm scenario. |
| Application note | For eligible ARC/BSP changes, enter 7JCU6 in OSI; use UAIRROPS in OSI for eligible self-refunds. Verify terms at the waiver URL before application. |
|
Recommendations
TBD
|
|