Peak Travel Seasons for Flight Delays and Cancellations Statistics
Summer is when the most people fly, and it is also when flights are most likely to run late. In the United States, only 69.2% of flights arrived on time in July 2025. In Europe, the average departure that month left 21 minutes behind schedule.
The calendar is one of the few delay risks a traveller can actually control. The month, the day of the week and the hour you choose all move the odds of a disrupted trip, and the data below shows by how much. It draws on full-year 2025 figures from the US Bureau of Transportation Statistics (BTS), EUROCONTROL and the TSA, plus 2026 data published up to September 2026.
Key Peak Travel Season Delay Statistics at a Glance
- 76.4% of US flights arrived on time in 2025, down from 78.1% in 2024.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2025 - 1.53% of US flights were cancelled in 2025, up from 1.36% a year earlier.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2025 - July 2025 was the worst month for US punctuality at 69.2% on time, while September was the best at 83.1%.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2025 - January 2026 had a 4.82% US cancellation rate, the highest monthly figure since at least January 2024, as Winter Storm Fern grounded flights.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2026 - US cancellations ran at 2.31% in January-July 2026, against 1.72% in the same months of 2025.
Source: BTS, Airline On-Time Statistics and Delay Causes, 2026 - Weather was behind 37.7% of delayed US flights in July 2025, nearly double its 19.7% share in October.
Source: BTS, Weather's Share of Delayed Flights, 2025 - Only 69% of flights arrived on time over the 2025 Independence Day period, the weakest of the five US holiday windows.
Source: BTS, Holiday Flight Delays, 2025 - Thanksgiving 2025 on-time arrivals fell to 74%, from 83% at Thanksgiving 2024, with cancellations up from 0.26% to 1.65%.
Source: BTS, Holiday Flight Delays, 2025 - The TSA screened a record 3.13 million people on Sunday 30 November 2025, the Sunday after Thanksgiving.
Source: TSA, Checkpoint Travel Numbers, 2025 - Tuesday was the quietest day at US airports in 2025, with 21% fewer travellers screened than an average Sunday.
Source: TSA, Checkpoint Travel Numbers, 2025 - A 6 a.m. US departure had a 1 in 9 chance of delay or cancellation in summer 2025, rising to 1 in 3 by the 3 p.m. hour.
Source: AAA Northeast analysis of BTS data, 2026 - Europe's average departure delay peaked at 21.0 minutes per flight in July 2025, against a low of 8.8 minutes in March.
Source: EUROCONTROL, All-Causes Delay to Air Transport in Europe, 2025 - European flights averaged a 14.7-minute departure delay across 2025, rising to 18.2 minutes in June-August.
Source: EUROCONTROL, Network Operations Report 2025 - Weather caused 32.0% of all European ATFM delay in 2025, while ATC capacity accounted for 42.7% of en-route delay.
Source: EUROCONTROL, Network Operations Report 2025 - 81.3% of Europe's first-wave morning flights departed on time in 2025, against 70.1% across the whole day.
Source: EUROCONTROL, Network Operations Report 2025 - August 2026 averaged 19.3 minutes of departure delay in Europe, worse than the 17.1 minutes of August 2025.
Source: EUROCONTROL, All-Causes Delay to Air Transport in Europe, August 2025 and August 2026 editions
US Flight On-Time Performance by Month, 2025 vs 2026
BTS tracks every flight operated by the large US carriers that report to the Department of Transportation. A flight counts as on time if it reaches the gate less than 15 minutes after its scheduled arrival. Watch how the 2025 line holds near 78-80% from January to April, sags hard in June and July, and then jumps in September.
Source: Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes (TranStats), monthly national data January 2025 to July 2026, accessed 24 September 2026. 2026 figures cover January-July only.
The gap between the best and worst month of 2025 was nearly 14 percentage points: 83.1% on time in September against 69.2% in July. June (70.2%) was almost as poor as July, which means the June-August stretch averaged about 72%. December was the other weak spot at 71.7%, as holiday demand met winter weather. Much of the summer slump is knock-on delay. In July 2025, 10.7% of all flights were late mainly because the aircraft arrived late from its previous trip, roughly double the 5.5% recorded in September. July 2026 (69.5%) landed almost exactly where July 2025 did, so the seasonal penalty has not eased. For a wider view of how often flights go wrong worldwide, see our global flight disruption statistics.
Flight Cancellation Rates by Month: Winter Storms Hit Hardest
Cancellations follow a different calendar from delays. Summer thunderstorms slow thousands of flights at once, but it usually takes snow, ice or a system-wide failure to wipe out whole banks of departures. The highest bars below sit in winter and at moments of crisis.
Source: Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes (TranStats), monthly national data January 2025 to July 2026; Federal Aviation Administration, emergency order on flight reductions, November 2025. 2026 figures cover January-July only.
January was the worst month in both years: 3.13% of flights cancelled in January 2025 and 4.82% in January 2026, when Winter Storm Fern grounded thousands of flights across the southern and eastern US in the last week of the month. November 2025 (2.60%) is the outlier with a man-made cause. During the federal government shutdown, the FAA ordered airlines to cut flights at 40 major airports from 7 November, starting at 4% of operations, and only lifted the order on 17 November. September and October 2025 were the calmest months, with cancellations at about 0.5%. The early months of 2026 have pushed the year-to-date rate to 2.31% for January-July, about a third higher than the 1.72% of the same period in 2025.
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Europe Flight Delays by Month: July Peak, March Low
EUROCONTROL's Central Office for Delay Analysis (CODA) averages the departure delay of every flight in the ECAC area, the 40-plus countries covered by European air traffic management. The two lines show the same shape as in the US, with one difference: Europe's delay season runs later into the autumn.
Source: EUROCONTROL, All-Causes Delay to Air Transport in Europe (CODA), monthly editions January 2025 to August 2026 (latest published 22 September 2026). 2026 figures cover January-August only.
July 2025 averaged 21.0 minutes of departure delay per flight, nearly two and a half times March's 8.8 minutes. Reactionary delay, where a late inbound aircraft makes the next departure late, contributed 9.5 of those 21 minutes, about 45%. September 2025 (18.1 minutes) was worse than June (16.0), a reminder that European ATC strikes and late-summer storms often extend the peak. Winter has its own spikes: January 2026 hit 18.1 minutes, as snow and low visibility disrupted Paris Charles de Gaulle, Amsterdam Schiphol and both Istanbul airports. August 2026 (19.3 minutes) finished above August 2025 (17.1 minutes), so summer 2026 ended on a worse note than the one before it. Airline-level results are covered in our most unreliable airlines in Europe statistics.
Weather's Share of US Flight Delays by Month
BTS measures weather's full footprint on delays, which goes beyond flights coded as "extreme weather". It adds the weather part of air traffic system delays and the weather part of knock-on delays. The bars show weather's share of all delayed flights; the line shows its share of delay minutes inside the National Aviation System (NAS), meaning air traffic control and airport constraints.
Source: Bureau of Transportation Statistics, Weather's Share of Delayed Flights and Weather's Share of NAS Delays (TranStats, FAA OPSNET data), January-December 2025, accessed 24 September 2026.
Weather accounted for 30.2% of delayed US flights in 2025 overall, peaking at 37.7% in July and dropping to 19.7% in October. Inside the air traffic system, weather drove 73.3% of July's NAS delay minutes, the season of afternoon thunderstorms that close departure routes out of New York, Chicago and Atlanta. October tells a different story. Non-weather NAS delays hit their 2025 high that month, with 28,465 flights held up, as the 43-day federal shutdown that began on 1 October left air traffic controllers working unpaid. The practical lesson: summer delays are mostly weather you cannot predict weeks ahead, while autumn and spring delays depend more on how the system is staffed and scheduled.
Weather vs Air Traffic Control Delays in European Summers
In Europe, the Network Manager issues air traffic flow management (ATFM) slots when more aircraft want to use a sector or airport than controllers can safely handle, holding flights on the ground. Summer is when these slots bite hardest. Compare the weather and ATC capacity bars across three summers.
Source: EUROCONTROL, Special FlashBriefing: Overview of the performance of the European aviation network in Summer 2025 (June-August), September 2025. The three cause categories do not add up to the total, which also includes disruptions, events and industrial action.
Summer 2025 ATFM delay fell to 3.9 minutes per flight, from 5.4 in summer 2024, even as traffic rose 3%. Weather and ATC capacity tied at 1.4 minutes each, so weather made up about 36% of summer ATFM delay. Across the whole of 2025, weather's share was 32.0%, while ATC capacity caused 42.7% of en-route delay. The two interact: when thunderstorms close one block of airspace, flights re-route into neighbouring sectors that are already full. July is the pressure point. En-route ATFM delay averaged 4.0 minutes per flight in July 2025, about 2.4 times the 1.67-minute annual average, and a French ATC strike on 3-4 July alone generated 326,083 minutes of en-route delay and at least 3,343 cancellations.
| Europe, 2025 | Summer (June-August) | Full year |
|---|---|---|
| Average departure delay per flight | 18.2 min | 14.7 min |
| Average arrival delay per flight | 14.6 min | 11.7 min |
| Arrival punctuality (within 15 min) | 71% | 75.4% |
| ATFM delay per flight | 3.9 min | 2.35 min |
Source: EUROCONTROL, Network Operations Report 2025 (edition 1.0, 4 May 2026); summer ATFM delay and summer arrival punctuality from the Summer 2025 FlashBriefing. Full-year ATFM delay per flight = 1.67 min en-route + 0.68 min airport.
Holiday Flight Delays: Thanksgiving, Christmas and July 4th
BTS publishes on-time results for fixed travel windows around each major US holiday. Holidays combine peak loads with little spare capacity to recover. The dashed line marks the 2025 national average of 76.4%, so any bar to its left was worse than a typical day.
Source: Bureau of Transportation Statistics, On-Time Performance: Holiday Flight Delays (TranStats), 2024-2025 holiday windows in the chart, 2022 and 2023 figures cited in the text, accessed 24 September 2026; national average from BTS Airline On-Time Statistics, 2025.
The Independence Day window was the worst holiday to fly in 2025: 69% of flights arrived on time and 2.79% were cancelled, as July thunderstorms met peak summer schedules. It was also the weakest holiday in 2023 (70%). Thanksgiving 2025 slipped to 74% on time, and cancellations jumped more than sixfold, from 0.26% to 1.65%. The same holiday weekend still produced the busiest day in TSA history: 3.13 million people screened on Sunday 30 November 2025. The winter holiday period reached 72% on time. Christmas carries the biggest tail risk: in 2022 only 60% of holiday flights arrived on time and 8.23% were cancelled. Labor Day is the safest bet, at 83% on time in 2025. Europe's holiday peak lands in late summer: the network set its busiest week on record from 25 to 31 August 2025, with 250,291 flights. See our TSA checkpoint travel numbers for daily US passenger volumes.
Best Time of Day to Fly to Avoid Delays
Delays build as the day goes on. Early flights usually use aircraft that sat overnight at the gate, so they start clean. Every later rotation inherits whatever went wrong earlier. The chart shows how quickly the risk climbs in a US summer.
Source: AAA Northeast analysis of Bureau of Transportation Statistics on-time data for June-August 2025, published 2026. Percentages are converted from the published odds (1 in 9, 1 in 5, 1 in 3).
A flight in the 6 a.m. hour had roughly an 11% chance of being delayed or cancelled in summer 2025. By 10 a.m. the risk was 1 in 5, and by 3 p.m. it was 1 in 3. European data points the same way. EUROCONTROL's first rotation, the first departures of the day, recorded 81.3% departure punctuality in 2025, 11.2 points better than the 70.1% all-day figure, and 86.8% arrival punctuality against 75.4%. The knock-on effect is measurable: in summer 2025, each minute of ground delay on a first-wave flight turned into 2.2 minutes of arrival delay later in the network.
Lowest-risk booking pattern: fly in September, October or early spring, take the first departure of the day, and choose a midweek date. Avoid the Independence Day window, the Sunday after Thanksgiving and late December to January, when winter storms drive cancellations. On connections, leave extra time on afternoon and evening legs in June and July.
Busiest Days of the Week to Fly in the US
BTS does not publish a national weekday breakdown in its summary tables, but TSA checkpoint counts show where demand concentrates. Crowded days mean fuller flights, longer lines and fewer empty seats for rebooking when something goes wrong.
Source: Transportation Security Administration, TSA Checkpoint Travel Numbers, 2025 daily data (365 days), averaged by day of week. Values in millions, rounded to two decimals.
Sunday was the busiest day of the week in 2025, averaging 2.74 million travellers screened, followed by Friday (2.68 million) and Thursday (2.65 million). Tuesday averaged 2.16 million, about 21% below Sunday, with Wednesday and Saturday close behind at 2.27 million. Six of the ten busiest days of 2025 were Sundays, most of them in June and July. The TSA screened 906.7 million people over the year. If your dates are flexible, a Tuesday or Wednesday departure puts you on emptier flights, which matters most when a cancellation forces a rebooking. For airport-level traffic, see our busiest airports statistics.
Outlook: What 2026 Data Shows So Far
The seasonal pattern is holding in 2026. US on-time arrivals for January-July reached 75.1%, close to the 75.5% of the same months in 2025, but cancellations are running higher because of a harsh January. July 2026 repeated July 2025 almost to the decimal point, at 69.5% on time. In Europe, spring 2026 was calm, then August pushed average departure delay to 19.3 minutes, above the previous August. EUROCONTROL's own report says the network still lacks structural capacity, driven largely by air traffic controller shortages, so summer delays remain likely until that changes. For travellers, the most dependable levers stay the same: an early departure, a shoulder-season month and a midweek date.
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References and Sources
- Bureau of Transportation Statistics, Airline On-Time Statistics and Delay Causes (incl. Weather's Share of Delayed Flights and NAS Delay by Cause), TranStats, data through July 2026, accessed 24 September 2026
- Bureau of Transportation Statistics, On-Time Performance: Holiday Flight Delays, TranStats, data through July 2026, accessed 24 September 2026
- EUROCONTROL Network Manager, Network Operations Report 2025, edition 1.0, 4 May 2026 (published 5 May 2026)
- EUROCONTROL, Special FlashBriefing: Overview of the performance of the European aviation network in Summer 2025 (June-August), September 2025
- EUROCONTROL CODA, All-Causes Delay to Air Transport in Europe, monthly editions January 2025 to August 2026 (August 2026 edition published 22 September 2026)
- Transportation Security Administration, TSA Checkpoint Travel Numbers 2025, accessed 24 September 2026
- Federal Aviation Administration, DOT and FAA Announce Temporary 10% Reduction in Flights at 40 Airports, November 2025
- Federal Aviation Administration, Cancellation of Emergency Order Establishing Operating Requirements, November 2025
- AAA Northeast, Morning Flights Offer Best Chance of Avoiding Summer Travel Delays Across the Northeast and United States (analysis of 2025 BTS data), 2026
Methodology Note
US monthly, annual and holiday figures come directly from BTS TranStats queries run on 24 September 2026 and cover the reporting carriers in the Airline Service Quality Performance data; a flight is on time if it arrives less than 15 minutes late, and weather's share of delays follows the BTS method (extreme weather plus the weather portions of NAS and late-aircraft delays). Holiday rows for 2026 were excluded because the windows were incomplete, and holiday percentages are published rounded to whole numbers. European monthly delays use EUROCONTROL CODA all-causes averages, which rest on partial airline reporting (52-65% of IFR flights depending on the month); annual and summer figures use the final Network Operations Report 2025. Where EUROCONTROL sources differ, the final annual report was preferred: en-route ATC capacity is given as 42.7% of en-route delay (42.4% in its executive summary). Summer arrival punctuality appears as 71% for June-August (FlashBriefing) and 72.3% in the annual report, which uses a longer summer window; the table uses the June-August figure to match its other rows. The TSA record of 3.13 million reflects the current daily table (3,134,613; the initial announcement said 3,133,924). Derived values are ours: full-year ATFM delay per flight (1.67 + 0.68 = 2.35 min), weather's summer ATFM share (1.4 / 3.9 = 36%), weekday averages from 365 days of TSA data, and time-of-day percentages converted from AAA's published odds. The time-of-day figures are a secondary analysis of BTS data, and weekday volumes measure demand rather than delay rates. No forecasts are used; 2026 values are actual data for the months published so far.
Author:
Amy LancelotteJob/Position: Senior Writer & Content Strategist
Amy Lancelotte is a Senior Content Writer and editorial contributor at AirAdvisor with over seven years of experience producing research-based articles for international audiences. Her work focuses on travel, aviation, and air passenger rights, with an emphasis on factual accuracy, verified data, and clear, reader-first explanations.
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