UK FLIGHT DELAY INDEX

derived from CAA punctuality statistics for UK reporting airports

How often are these flights late or cancelled?

Japan

In the twelve months from July 2025 to June 2026, 21.4% of 1,735 movements arriving into the UK were disrupted — more than fifteen minutes late or cancelled at short notice.

Put the other way round, 78.6% of 1,735 movements met the fifteen-minute convention. These are historical observations, not a forecast.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Source: CAA punctuality statistics · snapshot 17/08/2026 10:24 · method route-record-v2.1 · Versioned claims, formulas and entity mapping.

0 operations (0.00%) excluded because their published percentages could not be reconciled to whole numbers. Excluded operations enter neither the numerator nor the denominator. Outcome figures and comparisons are unavailable when the excluded share exceeds fifteen percent.

The four numbers at a glance

21.4% of 1,735 movements were disrupted over July 2025 to June 2026.

Average delay covers delayed movements only. Its range reflects rounded source means and the unknown count of exactly punctual movements.

DisruptionShort-notice cancellationsDelay among delayed movementsOver three hours
21.4% of 1,735 movements0.8% of 1,735 movements30.1–73.8 minutes; delayed denominator 357–8190.6% of 1,735 movements
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

When late, how late?

0.6% of 1,735 movements passed the three-hour mark.

The ladder shows how many movements crossed each threshold. Cancellations are separate: 0.8% of 1,735 movements.

DelayShare and sampleOne event per movements
More than 15 minutes20.6% of 1,735 movements4.9
More than 30 minutes10.9% of 1,735 movements9.2
More than 60 minutes5.2% of 1,735 movements19.1
More than 120 minutes2.4% of 1,735 movements42.3
More than 180 minutes0.6% of 1,735 movements173.5
More than 360 minutes0.2% of 1,735 movements433.8
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Slightly late or occasionally a disaster?

2.4% of 1,735 movements passed two hours.

The histogram shows the published delay bands. Bucket shares use all reported operations, including unmatched records; cancellations are reported separately.

Nine delay buckets, minutes; share of all recorded operations>15 early42824.7%15–1 early47427.3%0–15 late46226.6%16–301689.7%31–60985.6%61…120502.9%121…180311.8%181…36060.3%>36040.2%D=1,735
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Better or worse since the start of the archive?

Best month: Dec 2020, no events in 54 movements. Worst month: Aug 2023, 41.0% of 144 movements.

The line traces every month. Lower disruption is better; gaps are never zeros. Pandemic readings describe a different operating regime.

Monthly disruption share; gaps mean no published dataJan 2018: 25.5%; sample: 1452018Feb 2018: 5.4%; sample: 147Mar 2018: 8.5%; sample: 164Apr 2018: 12.0%; sample: 158May 2018: 9.6%; sample: 157Jun 2018: 5.0%; sample: 141Jul 2018: 7.4%; sample: 162Aug 2018: 14.2%; sample: 162Sep 2018: 12.7%; sample: 158Oct 2018: 19.1%; sample: 157Nov 2018: 13.3%; sample: 158Dec 2018: 12.7%; sample: 158Jan 2019: 5.0%; sample: 1612019Feb 2019: 16.2%; sample: 148Mar 2019: 15.9%; sample: 164Apr 2019: 16.5%; sample: 176May 2019: 9.5%; sample: 179Jun 2019: 15.9%; sample: 176Jul 2019: 15.9%; sample: 182Aug 2019: 17.7%; sample: 181Sep 2019: 20.3%; sample: 172Oct 2019: 31.1%; sample: 180Nov 2019: 21.6%; sample: 171Dec 2019: 34.7%; sample: 170Jan 2020: 25.3%; sample: 1662020Feb 2020: 32.9%; sample: 164Mar 2020: 9.2%; sample: 163Apr 2020: 6.0%; sample: 50May 2020: 0.0%; sample: 27Jun 2020: 0.0%; sample: 24Jul 2020: 2.8%; sample: 36Aug 2020: 3.7%; sample: 27Sep 2020: 6.7%; sample: 30Oct 2020: 2.1%; sample: 48Nov 2020: 2.3%; sample: 44Dec 2020: 0.0%; sample: 54Jan 2021: 0.0%; sample: 552021Feb 2021: 2.2%; sample: 46Mar 2021: 6.5%; sample: 62Apr 2021: 1.4%; sample: 73May 2021: 5.7%; sample: 70Jun 2021: 3.6%; sample: 56Jul 2021: 8.1%; sample: 86Aug 2021: 5.6%; sample: 89Sep 2021: 11.7%; sample: 77Oct 2021: 8.8%; sample: 80Nov 2021: 1.6%; sample: 64Dec 2021: 1.5%; sample: 65Jan 2022: 1.8%; sample: 552022Feb 2022: 2.1%; sample: 48Mar 2022: 39.4%; sample: 66Apr 2022: 13.3%; sample: 45May 2022: 12.2%; sample: 41Jun 2022: 7.1%; sample: 56Jul 2022: 11.8%; sample: 76Aug 2022: 1.3%; sample: 79Sep 2022: 5.1%; sample: 78Oct 2022: 1.2%; sample: 81Nov 2022: 26.6%; sample: 94Dec 2022: 26.1%; sample: 111Jan 2023: 29.1%; sample: 1172023Feb 2023: 15.5%; sample: 110Mar 2023: 15.0%; sample: 127Apr 2023: 34.3%; sample: 137May 2023: 16.3%; sample: 141Jun 2023: 36.5%; sample: 137Jul 2023: 24.6%; sample: 142Aug 2023: 41.0%; sample: 144Sep 2023: 32.1%; sample: 137Oct 2023: 19.4%; sample: 139Nov 2023: 23.3%; sample: 133Dec 2023: 8.2%; sample: 122Jan 2024: 36.0%; sample: 1252024Feb 2024: 14.2%; sample: 127Mar 2024: 14.5%; sample: 138Apr 2024: 15.9%; sample: 151May 2024: 13.5%; sample: 155Jun 2024: 23.3%; sample: 150Jul 2024: 25.2%; sample: 155Aug 2024: 23.2%; sample: 155Sep 2024: 26.8%; sample: 149Oct 2024: 17.1%; sample: 152Nov 2024: 15.0%; sample: 133Dec 2024: 12.5%; sample: 136Jan 2025: 11.6%; sample: 1292025Feb 2025: 28.7%; sample: 115Mar 2025: 9.8%; sample: 133Apr 2025: 16.0%; sample: 150May 2025: 17.4%; sample: 155Jun 2025: 27.3%; sample: 150Jul 2025: 35.7%; sample: 157Aug 2025: 35.0%; sample: 157Sep 2025: 20.7%; sample: 150Oct 2025: 8.6%; sample: 152Nov 2025: 4.5%; sample: 133Dec 2025: 21.9%; sample: 137Jan 2026: 16.1%; sample: 1242026Feb 2026: 15.6%; sample: 122Mar 2026: 38.6%; sample: 145Apr 2026: 15.7%; sample: 153May 2026: 13.5%; sample: 156Jun 2026: 26.8%; sample: 149Pandemic regime Jun 2020Summer 2022 breakdown Jul 2022NATS system failure Aug 2023Heathrow fire closure Mar 2025100%0%
Every monthly observation
MonthDisruption on arrivals
Jan 201825.5% of 145 movements
Feb 20185.4% of 147 movements
Mar 20188.5% of 164 movements
Apr 201812.0% of 158 movements
May 20189.6% of 157 movements
Jun 20185.0% of 141 movements
Jul 20187.4% of 162 movements
Aug 201814.2% of 162 movements
Sep 201812.7% of 158 movements
Oct 201819.1% of 157 movements
Nov 201813.3% of 158 movements
Dec 201812.7% of 158 movements
Jan 20195.0% of 161 movements
Feb 201916.2% of 148 movements
Mar 201915.9% of 164 movements
Apr 201916.5% of 176 movements
May 20199.5% of 179 movements
Jun 201915.9% of 176 movements
Jul 201915.9% of 182 movements
Aug 201917.7% of 181 movements
Sep 201920.3% of 172 movements
Oct 201931.1% of 180 movements
Nov 201921.6% of 171 movements
Dec 201934.7% of 170 movements
Jan 202025.3% of 166 movements
Feb 202032.9% of 164 movements
Mar 20209.2% of 163 movements
Apr 20206.0% of 50 movements
May 2020no events in 27 movements — small sample, not ranked
Jun 2020no events in 24 movements — small sample, not ranked
Jul 20202.8% of 36 movements — small sample, not ranked
Aug 20203.7% of 27 movements — small sample, not ranked
Sep 20206.7% of 30 movements — small sample, not ranked
Oct 20202.1% of 48 movements — small sample, not ranked
Nov 20202.3% of 44 movements — small sample, not ranked
Dec 2020no events in 54 movements
Jan 2021no events in 55 movements
Feb 20212.2% of 46 movements — small sample, not ranked
Mar 20216.5% of 62 movements
Apr 20211.4% of 73 movements
May 20215.7% of 70 movements
Jun 20213.6% of 56 movements
Jul 20218.1% of 86 movements
Aug 20215.6% of 89 movements
Sep 202111.7% of 77 movements
Oct 20218.8% of 80 movements
Nov 20211.6% of 64 movements
Dec 20211.5% of 65 movements
Jan 20221.8% of 55 movements
Feb 20222.1% of 48 movements — small sample, not ranked
Mar 202239.4% of 66 movements
Apr 202213.3% of 45 movements — small sample, not ranked
May 202212.2% of 41 movements — small sample, not ranked
Jun 20227.1% of 56 movements
Jul 202211.8% of 76 movements
Aug 20221.3% of 79 movements
Sep 20225.1% of 78 movements
Oct 20221.2% of 81 movements
Nov 202226.6% of 94 movements
Dec 202226.1% of 111 movements
Jan 202329.1% of 117 movements
Feb 202315.5% of 110 movements
Mar 202315.0% of 127 movements
Apr 202334.3% of 137 movements
May 202316.3% of 141 movements
Jun 202336.5% of 137 movements
Jul 202324.6% of 142 movements
Aug 202341.0% of 144 movements
Sep 202332.1% of 137 movements
Oct 202319.4% of 139 movements
Nov 202323.3% of 133 movements
Dec 20238.2% of 122 movements
Jan 202436.0% of 125 movements
Feb 202414.2% of 127 movements
Mar 202414.5% of 138 movements
Apr 202415.9% of 151 movements
May 202413.5% of 155 movements
Jun 202423.3% of 150 movements
Jul 202425.2% of 155 movements
Aug 202423.2% of 155 movements
Sep 202426.8% of 149 movements
Oct 202417.1% of 152 movements
Nov 202415.0% of 133 movements
Dec 202412.5% of 136 movements
Jan 202511.6% of 129 movements
Feb 202528.7% of 115 movements
Mar 20259.8% of 133 movements
Apr 202516.0% of 150 movements
May 202517.4% of 155 movements
Jun 202527.3% of 150 movements
Jul 202535.7% of 157 movements
Aug 202535.0% of 157 movements
Sep 202520.7% of 150 movements
Oct 20258.6% of 152 movements
Nov 20254.5% of 133 movements
Dec 202521.9% of 137 movements
Jan 202616.1% of 124 movements
Feb 202615.6% of 122 movements
Mar 202638.6% of 145 movements
Apr 202615.7% of 153 movements
May 202613.5% of 156 movements
Jun 202626.8% of 149 movements
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

What did the big disruptions do here?

Each event is compared with the twelve preceding calendar months and the first later return to baseline.

A worse month is not proof the named event caused it. The open data carry no delay-cause field. Recovery is observed for at most eight subsequent months.

EventDirectionDisruption that monthBaseline beforeReturn to baseline
Pandemic regime · Jun 2020Arrivalsno events in 24 movements — small sample, not ranked19.2% across 1,802 flightsreturned the next month
Pandemic regime · Jun 2020Departuresno events in 25 movements — small sample, not ranked16.6% across 1,794 flightsreturned the next month
Summer 2022 breakdown · Jul 2022Arrivals11.8% of 76 movements9.4% across 772 flightsreturned the next month
Summer 2022 breakdown · Jul 2022Departures74.7% of 75 movements20.6% across 774 flightsreturned after 4 months
NATS system failure · Aug 2023Arrivals41.0% of 144 movements19.3% across 1,354 flightsreturned after 4 months
NATS system failure · Aug 2023Departures33.3% of 141 movements30.6% across 1,355 flightsreturned after 2 months
Heathrow fire closure · Mar 2025Arrivals9.8% of 133 movements19.0% across 1,718 flightsreturned the next month
Heathrow fire closure · Mar 2025Departures17.8% of 135 movements24.5% across 1,713 flightsreturned the next month
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Which time of year has been hardest?

Highest median: Jun, 23.3% across 7 months. Lowest median: May, 13.5% across 7 months.

Even the same calendar month differs across years. This is a record, not a forecast; pandemic years are excluded from the summaries.

Each cell is one calendar month of one year; the number is the share of that month’s arrivals that were disrupted. Darker means worse. A blank cell means no published data, not zero.

Seasonality: calendar month by year; share and nJanFebMarAprMayJunJulAugSepOctNovDec20195.0% of 161 movements16.2% of 148 movements15.9% of 164 movements16.5% of 176 movements9.5% of 179 movements15.9% of 176 movements15.9% of 182 movements17.7% of 181 movements20.3% of 172 movements31.1% of 180 movements21.6% of 171 movements34.7% of 170 movements202025.3% of 166 movements32.9% of 164 movements9.2% of 163 movements6.0% of 50 movementsno events in 27 movements †no events in 24 movements †2.8% of 36 movements †3.7% of 27 movements †6.7% of 30 movements †2.1% of 48 movements †2.3% of 44 movements †no events in 54 movements2021no events in 55 movements2.2% of 46 movements †6.5% of 62 movements1.4% of 73 movements5.7% of 70 movements3.6% of 56 movements8.1% of 86 movements5.6% of 89 movements11.7% of 77 movements8.8% of 80 movements1.6% of 64 movements1.5% of 65 movements20221.8% of 55 movements2.1% of 48 movements †39.4% of 66 movements13.3% of 45 movements †12.2% of 41 movements †7.1% of 56 movements11.8% of 76 movements1.3% of 79 movements5.1% of 78 movements1.2% of 81 movements26.6% of 94 movements26.1% of 111 movements202329.1% of 117 movements15.5% of 110 movements15.0% of 127 movements34.3% of 137 movements16.3% of 141 movements36.5% of 137 movements24.6% of 142 movements41.0% of 144 movements32.1% of 137 movements19.4% of 139 movements23.3% of 133 movements8.2% of 122 movements202436.0% of 125 movements14.2% of 127 movements14.5% of 138 movements15.9% of 151 movements13.5% of 155 movements23.3% of 150 movements25.2% of 155 movements23.2% of 155 movements26.8% of 149 movements17.1% of 152 movements15.0% of 133 movements12.5% of 136 movements202511.6% of 129 movements28.7% of 115 movements9.8% of 133 movements16.0% of 150 movements17.4% of 155 movements27.3% of 150 movements35.7% of 157 movements35.0% of 157 movements20.7% of 150 movements8.6% of 152 movements4.5% of 133 movements21.9% of 137 movements202616.1% of 124 movements15.6% of 122 movements38.6% of 145 movements15.7% of 153 movements13.5% of 156 movements26.8% of 149 movementsno datano datano datano datano datano data
Month-by-month table: median, observed range and sample
MonthMedianObserved rangeSample
Jan16.1%1.8–36.0%7 months, 856 flights
Feb15.5%2.1–28.7%7 months, 817 flights
Mar15.0%8.5–39.4%7 months, 937 flights
Apr15.9%12.0–34.3%7 months, 970 flights
May13.5%9.5–17.4%7 months, 984 flights
Jun23.3%5.0–36.5%7 months, 959 flights
Jul20.3%7.4–35.7%6 months, 874 flights
Aug20.5%1.3–41.0%6 months, 878 flights
Sep20.5%5.1–32.1%6 months, 844 flights
Oct18.1%1.2–31.1%6 months, 861 flights
Nov18.3%4.5–26.6%6 months, 822 flights
Dec17.3%8.2–34.7%6 months, 834 flights
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Which routes have the best and worst record?

Lowest disruption: LHR ↔ TOKYO-HANEDA, 21.2% of 1,730 movements. Highest disruption: LHR ↔ TOKYO-HANEDA, 21.2% of 1,730 movements.

The airline table uses this carrier on each route; airport and country tables combine carriers. Each figure is arrivals into its UK airport. Only sufficiently large exact samples enter the ordered comparison.

Observed disruption share by optionLhr ↔ Tokyo-Haneda21.2% of 1,730 flights
All route comparisons and sample flags
RouteDisruptionCancellationsSample flag
Heathrow ↔ Tokyo (Haneda)21.2% of 1,730 movements0.7% of 1,730 movementsdescriptive comparison
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Which UK airports appear in this record?

1 published groups have enough arrivals to describe.

These operations are not matched for season, aircraft or time of day. The table makes no causal comparison.

UK airportDisruptionSample flag
Heathrow21.3% of 1,734 movementsdescriptive comparison
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Arrivals vs departures

21.4% of 1,735 movements arrivals were disrupted, against 22.4% of 1,735 movements departures.

The directions have separate denominators. A departure delay does not establish late arrival at the final destination; legal conditions differ by direction and carrier.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Movements past the three-hour mark

0.6% of 1,735 movements were more than three hours late over July 2025 to June 2026.

Cancellation is counted separately and is not a three-hour delay. Monthly counts cannot establish a passenger claim.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Facts about this record

Japan appears from Jan 2018 to Jun 2026 with 12,292 arrivals.

The bounds describe the published record, not every commercial service. Final point is not necessarily a nonstop destination.

Archive route pairs: 7.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

What this data cannot tell you

Delay cause, individual passenger experience, commercial decisions and future performance are not established here.

Also absent are aircraft type, within-month time-of-day splits and cancellations made ahead of the short-notice reporting window.

0 operations (0.00%) excluded because their published percentages could not be reconciled to whole numbers. Excluded operations enter neither the numerator nor the denominator. Outcome figures and comparisons are unavailable when the excluded share exceeds fifteen percent.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Quick answers

These answers use the same populations and window as the tables above.

Every percentage retains its denominator.

How disrupted are these arrivals?

21.4% of 1,735 movements over July 2025 to June 2026.

How often are they cancelled?

0.8% of 1,735 movements at short notice.

How late is late?

30.1–73.8 minutes; delayed denominator 357–819

Are services improving?

The monthly line records past changes; it is not a forecast or a causal comparison.

Which routes are compared?

The route table uses separately identified UK airport and final-point pairs, with small samples flagged.

Does this cover my flight?

Only published aggregate movements; the circumstances of any individual flight are unknown.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

How this was calculated

Source: CAA punctuality statistics · snapshot 17/08/2026 10:24 · method route-record-v2.1 · Versioned claims, formulas and entity mapping.

Integer bucket counts are recovered from rounding intervals over D=M+C+U with their sum constrained to M. Ambiguous counts remain ranges; failed reconciliation is quarantined.

Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.

Your trip has already gone wrong

The monthly line and events table show whether your month was typical or unusual in the published record.

Nothing here decides an individual case or what a passenger may be owed.

CAA: the official route to complain
Definitions, denominators and limits

Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.