Delay Severity Index (operated flights)
4.26
Weighted severity among matched operated movements.
sample: 177,276 matched operated movements
Monthly report
June 2026
34.14%
UKFDI: disruption events per one hundred known operations.
| actual-mix | 34.14% |
|---|---|
| fixed-basket (June 2025 basket, coverage 94.53%) | 34.05% |
UK metrics
Short-notice cancellations
1.19%
Share of known operations.
sample: 179,402 known operations
Three-hour-plus gate delay
0.68%
Arrival or departure gate delay among known operations.
sample: 179,402 known operations
Average positive gate delay, as published by the CAA (early flights count as 0 minutes)
19.7 minutes
Mean among matched operated movements.
sample: 177,276 matched operated movements
Unmatched pressure
complete matching this month (0 unmatched movements)
Data-quality share of all reported operations.
sample: 179,402 all reported operations
Delay threshold ladder
| Observed outcome | Share | Known operations |
|---|---|---|
| Within 15 minutes | 65.86% | 179,402 |
| Within 30 minutes | 78.88% | 179,402 |
| Within 60 minutes | 90.16% | 179,402 |
| Within 120 minutes | 96.66% | 179,402 |
| Within 180 minutes | 98.14% | 179,402 |
| Within 360 minutes | 98.70% | 179,402 |
Ten attributable statistics
Actual-mix UKFDI was 34.14%. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 2126, "K_j": {"0_to_15_minutes_late": 56824, "121_to_180_minutes_late": 2646, "15_minutes_early_to_1_minute_early": 50857, "16_to_30_minutes_late": 23361, "181_to_360_minutes_late": 1008, "31_to_60_minutes_late": 20240, "61_to_120_minutes_late": 11663, "more_than_15_minutes_early": 10467, "more_than_360_minutes_late": 210}, "M": 177276, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | volume_weighted_disruption_share_of_known_operations |
| Scope | June 2026; UK reporting airports; United Kingdom reporting airports; ALL |
Fixed-basket UKFDI was 34.05% using the June 2025 basket with coverage 94.53%. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 2126, "K_j": {"0_to_15_minutes_late": 56824, "121_to_180_minutes_late": 2646, "15_minutes_early_to_1_minute_early": 50857, "16_to_30_minutes_late": 23361, "181_to_360_minutes_late": 1008, "31_to_60_minutes_late": 20240, "61_to_120_minutes_late": 11663, "more_than_15_minutes_early": 10467, "more_than_360_minutes_late": 210}, "M": 177276, "U": 0, "common_cells": 6378, "current_known_covered": 169594, "current_known_total": 179402, "prior_known_total": 176955, "prior_period": "202506", "prior_weight_covered": 0.94806589, "weighted_disruption_sum": 0.34046633} |
|---|---|
| Formula | Σ (known_cell(P−12) / known_total(P−12)) × disruption_cell(P), common cells only |
| Typed unit | fixed_basket_disruption_share_of_known_operations |
| Scope | June 2026; UK reporting airports; United Kingdom reporting airports; ALL |
Heathrow recorded 28.48% disruption. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 707, "K_j": {"0_to_15_minutes_late": 13581, "121_to_180_minutes_late": 326, "15_minutes_early_to_1_minute_early": 11723, "16_to_30_minutes_late": 4918, "181_to_360_minutes_late": 166, "31_to_60_minutes_late": 3526, "61_to_120_minutes_late": 1616, "more_than_15_minutes_early": 3114, "more_than_360_minutes_late": 56}, "M": 39026, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; HEATHROW; ALL |
Gatwick recorded 38.09% disruption. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 346, "K_j": {"0_to_15_minutes_late": 7670, "121_to_180_minutes_late": 448, "15_minutes_early_to_1_minute_early": 5895, "16_to_30_minutes_late": 3479, "181_to_360_minutes_late": 225, "31_to_60_minutes_late": 2978, "61_to_120_minutes_late": 1794, "more_than_15_minutes_early": 1542, "more_than_360_minutes_late": 24}, "M": 24055, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; GATWICK; ALL |
Manchester recorded 41.61% disruption. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 186, "K_j": {"0_to_15_minutes_late": 6085, "121_to_180_minutes_late": 312, "15_minutes_early_to_1_minute_early": 4090, "16_to_30_minutes_late": 2935, "181_to_360_minutes_late": 92, "31_to_60_minutes_late": 2701, "61_to_120_minutes_late": 1565, "more_than_15_minutes_early": 787, "more_than_360_minutes_late": 21}, "M": 18588, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; MANCHESTER; ALL |
Short-notice cancellations were 1.19% of known operations. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 2126, "K_j": {"0_to_15_minutes_late": 56824, "121_to_180_minutes_late": 2646, "15_minutes_early_to_1_minute_early": 50857, "16_to_30_minutes_late": 23361, "181_to_360_minutes_late": 1008, "31_to_60_minutes_late": 20240, "61_to_120_minutes_late": 11663, "more_than_15_minutes_early": 10467, "more_than_360_minutes_late": 210}, "M": 177276, "U": 0} |
|---|---|
| Formula | C / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; United Kingdom reporting airports; ALL |
Three-hour-plus gate delays were 0.68% of known operations. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 2126, "K_j": {"0_to_15_minutes_late": 56824, "121_to_180_minutes_late": 2646, "15_minutes_early_to_1_minute_early": 50857, "16_to_30_minutes_late": 23361, "181_to_360_minutes_late": 1008, "31_to_60_minutes_late": 20240, "61_to_120_minutes_late": 11663, "more_than_15_minutes_early": 10467, "more_than_360_minutes_late": 210}, "M": 177276, "U": 0} |
|---|---|
| Formula | (K_181_360 + K_360_plus) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; United Kingdom reporting airports; ALL |
65.86% of known operations were no more than fifteen minutes late. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 2126, "K_j": {"0_to_15_minutes_late": 56824, "121_to_180_minutes_late": 2646, "15_minutes_early_to_1_minute_early": 50857, "16_to_30_minutes_late": 23361, "181_to_360_minutes_late": 1008, "31_to_60_minutes_late": 20240, "61_to_120_minutes_late": 11663, "more_than_15_minutes_early": 10467, "more_than_360_minutes_late": 210}, "M": 177276, "U": 0} |
|---|---|
| Formula | (K_early_15_plus + K_early_1_15 + K_0_15) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; United Kingdom reporting airports; ALL |
Among airlines with at least 1,000 known operations, SAS had the lowest observed disruption at 20.91%. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 37, "K_j": {"0_to_15_minutes_late": 437, "121_to_180_minutes_late": 2, "15_minutes_early_to_1_minute_early": 445, "16_to_30_minutes_late": 128, "181_to_360_minutes_late": 0, "31_to_60_minutes_late": 58, "61_to_120_minutes_late": 14, "more_than_15_minutes_early": 22, "more_than_360_minutes_late": 0}, "M": 1106, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; SAS; ALL |
Among airlines with at least 1,000 known operations, TUI Airways Ltd had the highest observed disruption at 48.27%. Source: flightdelayindex.com, derived from CAA punctuality statistics, June 2026, UK reporting airports.
How to reproduce
| Source aggregates | {"C": 4, "K_j": {"0_to_15_minutes_late": 2841, "121_to_180_minutes_late": 140, "15_minutes_early_to_1_minute_early": 1042, "16_to_30_minutes_late": 1465, "181_to_360_minutes_late": 59, "31_to_60_minutes_late": 1340, "61_to_120_minutes_late": 724, "more_than_15_minutes_early": 144, "more_than_360_minutes_late": 25}, "M": 7780, "U": 0} |
|---|---|
| Formula | (Σ K_16+ + C) / (M + C) |
| Typed unit | share_of_known_operations |
| Scope | June 2026; UK reporting airports; TUI AIRWAYS LTD; ALL |
Lower observed disruption airports
| Airport | Known operations | Disruption |
|---|---|---|
| Southend | 584 | 17.98% |
| Liverpool (John Lennon) | 3,780 | 21.85% |
| Aberdeen | 2,390 | 22.55% |
| Belfast International | 4,178 | 25.37% |
| Belfast City (George Best) | 2,574 | 26.92% |
Higher observed disruption airports
| Airport | Known operations | Disruption |
|---|---|---|
| Exeter | 739 | 41.68% |
| Manchester | 18,774 | 41.61% |
| Edinburgh | 11,616 | 38.25% |
| Bournemouth | 1,060 | 38.21% |
| Birmingham | 9,030 | 38.11% |
Reconstructed matched operated movement counts
| On time to fifteen minutes late | 56,824 |
|---|---|
| One hundred twenty-one to one hundred eighty minutes late | 2,646 |
| Fifteen to one minute early | 50,857 |
| Sixteen to thirty minutes late | 23,361 |
| One hundred eighty-one to three hundred sixty minutes late | 1,008 |
| Thirty-one to sixty minutes late | 20,240 |
| Sixty-one to one hundred twenty minutes late | 11,663 |
| More than fifteen minutes early | 10,467 |
| More than three hundred sixty minutes late | 210 |
Quick answers
What does this record cover?
Published CAA movements, with arrivals and departures kept separate.
Does this predict my flight?
No. Historical monthly aggregates cannot establish the outcome or circumstances of an individual flight.