RAVeL W6 Au fil de l'eau: which way and when to ride
The best month for RAVeL W6 Au fil de l'eau is September: 76% of days were dry with highs of 10–30 °C. In September, riding Erquelinnes → Chaudfontaine meant an average tailwind of 4.2 km/h (ERA5 2006–2025, daytime 9:00–18:00).
Weather by month
| Month | Good days | Rain days ≥ 1 mm | Rain, mm | Avg high | Days ≥ 30 °C | Days < 10 °C | Daylight, h |
|---|---|---|---|---|---|---|---|
| January | 5% | 30% | 80 | 5 °C | 0% | 88% | 8.5 † |
| February | 13% | 30% | 68 | 7 °C | 0% | 80% | 10.0 † |
| March | 40% | 28% | 67 | 10 °C | 0% | 50% | 11.7 |
| April | 63% | 26% | 49 | 14 °C | 0% | 21% | 13.7 |
| May | 69% | 30% | 72 | 18 °C | 0% | 3% | 15.4 |
| June | 69% | 29% | 80 | 21 °C | 2% | 0% | 16.4 |
| July | 67% | 28% | 78 | 23 °C | 6% | 0% | 16.0 |
| August | 65% | 30% | 84 | 22 °C | 6% | 0% | 14.5 |
| September | 76% | 23% | 62 | 19 °C | 1% | 0% | 12.5 |
| October | 69% | 23% | 72 | 15 °C | 0% | 10% | 10.6 † |
| November | 29% | 29% | 70 | 9 °C | 0% | 57% | 8.9 † |
| December | 9% | 29% | 84 | 6 °C | 0% | 82% | 8.0 † |
Best months are all months within 3 percentage points of the best one. † less than 11 hours of daylight — long stages get tight.
Wind by month
| Month | Wind Chaudfontaine → Erquelinnes, km/h | Headwind > 15 km/h, Chaudfontaine → Erquelinnes | Headwind > 15 km/h, Erquelinnes → Chaudfontaine | Better way |
|---|---|---|---|---|
| January | −7.8 | 30% | 3% | Erquelinnes → Chaudfontaine |
| February | −5.9 | 27% | 7% | Erquelinnes → Chaudfontaine |
| March | −3.8 | 22% | 9% | Erquelinnes → Chaudfontaine |
| April | −1.2 | 14% | 8% | either |
| May | −3.1 | 17% | 6% | Erquelinnes → Chaudfontaine |
| June | −3.8 | 17% | 3% | Erquelinnes → Chaudfontaine |
| July | −6.6 | 23% | 1% | Erquelinnes → Chaudfontaine |
| August | −6.5 | 20% | 1% | Erquelinnes → Chaudfontaine |
| September | −4.2 | 17% | 4% | Erquelinnes → Chaudfontaine |
| October | −5.3 | 20% | 3% | Erquelinnes → Chaudfontaine |
| November | −7.0 | 24% | 2% | Erquelinnes → Chaudfontaine |
| December | −8.2 | 29% | 2% | Erquelinnes → Chaudfontaine |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | W | −4.1 |
| 25–51 | SW | −4.6 |
| 51–76 | W | −4.2 |
| 76–101 | W | −4.0 |
| 101–126 | W | −4.3 |
| 126–152 | SW | −4.1 |
| 152–160 | W | −3.9 |
How to read the numbers
Wind is the 10 m wind of a 25-km grid cell, daytime hours 9:00–18:00 local solar time; at saddle height in a sheltered valley it is weaker, on a coast or ridge stronger. A positive value is a tailwind. ERA5 slightly over-counts days with ≥ 1 mm of rain (by about 5–7 percentage points) and underestimates daily highs by 1–2 °C. Good day = less than 1 mm of rain between 9:00 and 18:00 (riding hours, local solar time) and a high between 10 and 30 °C; rain at night or in the evening does not spoil it.