How often does weather delay flights at Paris-Orly?
From January 2018 to September 2026, EUROCONTROL recorded arrival restrictions for weather (regulation reason W) at Paris-Orly (ORY) on 512 of 3,177 days (16%). The worst month is December: 24% of days and 0.4 minutes of weather delay per arriving flight on average. Calmest: March (9% of days). Weather caused 32% 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 | 20% | 9% | 0.49 |
| February | 19% | 10% | 0.54 |
| March | 9% | 5% | 0.23 |
| April | 11% | 7% | 0.24 |
| May | 19% | 11% | 0.50 |
| June | 17% | 10% | 0.48 |
| July | 11% | 8% | 0.27 |
| August | 11% | 7% | 0.30 |
| September | 15% | 7% | 0.24 |
| October | 15% | 6% | 0.46 |
| November | 23% | 15% | 0.84 |
| December | 24% | 10% | 0.39 |
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 50 (30%), week 2 (30%), week 45 (29%).
Year by year
| Year | Days with weather restrictions | Minutes per arriving flight | Arrivals |
|---|---|---|---|
| 2018 | 77 of 365 | 0.58 | 116,260 |
| 2019 | 59 of 365 | 0.43 | 110,860 |
| 2020 | 18 of 348 | 0.21 | 42,330 |
| 2021 | 31 of 365 | 0.12 | 60,317 |
| 2022 | 56 of 365 | 0.43 | 99,372 |
| 2023 | 67 of 365 | 0.29 | 104,364 |
| 2024 | 81 of 366 | 0.39 | 103,442 |
| 2025 | 66 of 365 | 0.47 | 109,463 |
| 2026 (Jan–Sep) | 57 of 273 | 0.47 | 82,854 |
2020–2021: far fewer flights during the pandemic.
Weather among all causes
| Cause of arrival regulation | Share of delay minutes |
|---|---|
| Weather | 32% |
| Aerodrome capacity | 32% |
| Industrial action (atc) | 12% |
| Atc staffing | 8% |
| Air traffic control capacity | 6% |
| Special event | 4% |
| Atc equipment | 4% |
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 | 16% | 1.6% | — |
| Fog or visibility under 800 m | 20% | 2.7% | 7.4× |
| Cloud base at or below 200 ft | 14% | 1.0% | — |
| Gusts of 30 knots or more | 8.4% | 5.4% | 1.5× |
| Crosswind of 20 knots or more on the best runway | 0.2% | 0.0% | — |
| Snow | 6.2% | 1.0% | — |
| Freezing rain or drizzle | 0.6% | 0.0% | — |
On 49% 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 3,177 days with full METAR coverage.
The heaviest days
| Date and reported weather | Weather delay, minutes | Arrivals | Minutes per arrival |
|---|---|---|---|
| 22 October 2019 Fog or visibility under 800 m; Cloud base at or below 200 ft | 13,961 | 259 | 53.9 |
| 7 February 2018 Snow | 7,751 | 200 | 38.8 |
| 16 November 2018 Fog or visibility under 800 m; Cloud base at or below 200 ft | 7,688 | 329 | 23.4 |
| 22 January 2019 Fog or visibility under 800 m; Cloud base at or below 200 ft; Snow | 7,507 | 257 | 29.2 |
| 29 August 2025 Thunderstorm reported | 6,504 | 330 | 19.7 |
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 LFPO, IATA ORY. Ranking by share of restriction days: 10 of 94 airports on this site.