How often does weather delay flights at Cologne-Bonn?
From January 2018 to September 2026, EUROCONTROL recorded arrival restrictions for weather (regulation reason W) at Cologne-Bonn (CGN) on 135 of 3,195 days (4.2%). The worst month is January: 8% of days and 0.2 minutes of weather delay per arriving flight on average. Calmest: March, April, July, October (3% of days). Weather caused 18% 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 | 8% | 6% | 0.25 |
| February | 4% | 2% | 0.09 |
| March | 3% | 3% | 0.07 |
| April | 3% | 3% | 0.07 |
| May | 5% | 4% | 0.09 |
| June | 5% | 4% | 0.13 |
| July | 3% | 2% | 0.06 |
| August | 4% | 3% | 0.12 |
| September | 4% | 3% | 0.15 |
| October | 3% | 2% | 0.09 |
| November | 7% | 5% | 0.16 |
| December | 4% | 4% | 0.14 |
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 47 (11%), week 5 (10%), week 21 (10%).
Year by year
| Year | Days with weather restrictions | Minutes per arriving flight | Arrivals |
|---|---|---|---|
| 2018 | 15 of 365 | 0.04 | 71,270 |
| 2019 | 14 of 365 | 0.09 | 70,735 |
| 2020 | 3 of 366 | 0.01 | 39,372 |
| 2021 | 10 of 365 | 0.07 | 45,321 |
| 2022 | 21 of 365 | 0.21 | 59,723 |
| 2023 | 26 of 365 | 0.20 | 58,648 |
| 2024 | 21 of 366 | 0.14 | 58,110 |
| 2025 | 11 of 365 | 0.12 | 58,532 |
| 2026 (Jan–Sep) | 14 of 273 | 0.11 | 43,407 |
2020–2021: far fewer flights during the pandemic.
Weather among all causes
| Cause of arrival regulation | Share of delay minutes |
|---|---|
| Aerodrome capacity | 76% |
| Weather | 18% |
| Equipment (non-atc) | 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 | 26% | 5.6% | 4.7× |
| Fog or visibility under 800 m | 13% | 2.5% | 4.9× |
| Cloud base at or below 200 ft | 10% | 1.3% | — |
| Gusts of 30 knots or more | 27% | 5.0% | 5.5× |
| Crosswind of 20 knots or more on the best runway | 1.5% | 0.1% | — |
| Snow | 13% | 3.5% | 3.6× |
| Freezing rain or drizzle | 2.2% | 0.2% | — |
On 34% 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 3,195 days with full METAR coverage.
The heaviest days
| Date and reported weather | Weather delay, minutes | Arrivals | Minutes per arrival |
|---|---|---|---|
| 23 October 2025 Gusts of 30 knots or more (gusts to 39 kt) | 2,347 | 221 | 10.6 |
| 4 August 2022 Thunderstorm reported | 2,304 | 207 | 11.1 |
| 30 January 2019 Snow | 2,096 | 175 | 12.0 |
| 6 September 2022 Thunderstorm reported | 2,005 | 200 | 10.0 |
| 21 February 2023 Fog or visibility under 800 m | 1,527 | 125 | 12.2 |
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 EDDK, IATA CGN. Ranking by share of restriction days: 36 of 94 airports on this site.