Wind — 1999
| Month | Châtelet | Gerpinnes | Difference |
|---|---|---|---|
| Jan | 19.9 km/h | – | – |
| Feb | 16.6 km/h | – | – |
| Mar | 14.9 km/h | – | – |
| Apr | 14.5 km/h | – | – |
| May | 12.7 km/h | – | – |
| Jun | 13.2 km/h | – | – |
| Jul | 12.5 km/h | – | – |
| Aug | 11.9 km/h | – | – |
| Sep |
| 14.3 km/h |
| – |
| – |
| Oct | 16.4 km/h | – | – |
| Nov | 16 km/h | – | – |
| Dec | 21 km/h | – | – |