How often does weather delay flights at Istanbul Atatürk (since 2019: cargo and business flights)?
From January 2018 to September 2026, EUROCONTROL recorded arrival restrictions for weather (regulation reason W) at Istanbul Atatürk (since 2019: cargo and business flights) (ISL) on 68 of 3,186 days (2.1%). The worst month is March: 6% of days and 1.1 minutes of weather delay per arriving flight on average. Calmest: April, August (0% of days). Weather caused 30% of all arrival-regulation delay minutes at this airport. Source: EUROCONTROL.
Month by month
| Month | Days with weather restrictions | Days with ≥ 1 min per arrival | Minutes per arriving flight |
|---|---|---|---|
| January | 5% | 3% | 0.65 |
| February | 5% | 3% | 1.35 |
| March | 6% | 4% | 1.11 |
| April | 0% | 0% | 0.00 |
| May | 1% | 0% | 0.09 |
| June | 2% | 2% | 0.32 |
| July | 1% | 1% | 0.30 |
| August | 0% | 0% | 0.00 |
| September | 2% | 2% | 0.43 |
| October | 1% | 0% | 0.06 |
| November | 1% | 1% | 0.18 |
| December | 1% | 1% | 0.10 |
Share of days on which EUROCONTROL's network manager limited arrivals because of weather at or around the airport (regulation reason W), 2018–2026. Minutes per arriving flight = weather-regulation delay ÷ all arrivals that month. Worst weeks of the year: week 5 (10%), week 2 (8%), week 9 (8%).
Year by year
| Year | Days with weather restrictions | Minutes per arriving flight | Arrivals |
|---|---|---|---|
| 2018 | 47 of 365 | 0.50 | 228,197 |
| 2019 | 21 of 365 | 0.83 | 66,265 |
| 2020 | 0 of 366 | 0.00 | 16,724 |
| 2021 | 0 of 365 | 0.00 | 17,253 |
| 2022 | 0 of 363 | 0.00 | 9,477 |
| 2023 | 0 of 361 | 0.00 | 8,505 |
| 2024 | 0 of 363 | 0.00 | 9,877 |
| 2025 | 0 of 365 | 0.00 | 10,037 |
| 2026 (Jan–Sep) | 0 of 273 | 0.00 | 7,869 |
2020–2021: far fewer flights during the pandemic.
Weather among all causes
| Cause of arrival regulation | Share of delay minutes |
|---|---|
| Aerodrome capacity | 66% |
| Weather | 30% |
| Special event | 3% |
Causes with at least 2% of all arrival-regulation delay minutes, 2018–2026.
What the weather was like on those days
| In the airport's weather reports (METAR, 05–21 UTC) | Days with weather restrictions | Other days | Ratio |
|---|---|---|---|
| Thunderstorm reported | 25% | 5.5% | 4.5× |
| Fog or visibility under 800 m | 7.4% | 0.8% | — |
| Cloud base at or below 200 ft | 1.5% | 0.1% | — |
| Gusts of 30 knots or more | 25% | 7.2% | 3.5× |
| Crosswind of 20 knots or more on the best runway | 13% | 1.9% | — |
| Snow | 10% | 2.2% | 4.7× |
| Freezing rain or drizzle | 0.0% | 0.0% | — |
On 44% of the restriction days none of these showed up in the airport's own reports: restrictions are also set on forecasts, for weather on the approach or elsewhere in the area, and when the wind direction forces a less efficient runway layout. The weather is what came with the delays, not proof of their cause. Based on 3,186 days with full METAR coverage.
The heaviest days
| Date and reported weather | Weather delay, minutes | Arrivals | Minutes per arrival |
|---|---|---|---|
| 11 March 2018 Fog or visibility under 800 m | 21,256 | 593 | 35.8 |
| 20 February 2019 Fog or visibility under 800 m | 18,593 | 574 | 32.4 |
| 17 January 2018 none of these in the airport's METAR | 7,643 | 594 | 12.9 |
| 24 February 2019 Fog or visibility under 800 m; Gusts of 30 knots or more; Snow (gusts to 31 kt) | 7,235 | 570 | 12.7 |
| 3 February 2018 none of these in the airport's METAR | 6,689 | 614 | 10.9 |
What these numbers cover
- Only delays from air traffic flow management (ATFM) regulations on arrivals are counted — not all delays, not departures, and not cancellations or diversions. A day with restrictions does not mean every flight was late.
- Airport ICAO code LTBA, IATA ISL. Ranking by share of restriction days: 54 of 94 airports on this site.