Véloroute de la Rance et de la Vilaine: which way and when to ride
The best month for Véloroute de la Rance et de la Vilaine is September: 80% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.1 km/h along the route (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 | 27% | 23% | 69 | 9 °C | 0% | 58% | 8.8 † |
| February | 43% | 21% | 57 | 10 °C | 0% | 44% | 10.2 † |
| March | 59% | 26% | 57 | 12 °C | 0% | 22% | 11.8 |
| April | 74% | 24% | 54 | 16 °C | 0% | 3% | 13.6 |
| May | 74% | 26% | 62 | 18 °C | 0% | 0% | 15.2 |
| June | 74% | 23% | 59 | 22 °C | 4% | 0% | 16.0 |
| July | 75% | 20% | 52 | 23 °C | 6% | 0% | 15.7 |
| August | 78% | 18% | 49 | 23 °C | 4% | 0% | 14.3 |
| September | 80% | 19% | 46 | 21 °C | 2% | 0% | 12.5 |
| October | 77% | 22% | 73 | 17 °C | 0% | 1% | 10.7 † |
| November | 61% | 24% | 74 | 12 °C | 0% | 19% | 9.2 † |
| December | 34% | 25% | 76 | 10 °C | 0% | 47% | 8.4 † |
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 Tréméreuc → Arzal, km/h | Headwind > 15 km/h, Tréméreuc → Arzal | Headwind > 15 km/h, Arzal → Tréméreuc | Better way |
|---|---|---|---|---|
| January | −3.1 | 18% | 7% | Arzal → Tréméreuc |
| February | −2.2 | 18% | 10% | Arzal → Tréméreuc |
| March | −0.6 | 16% | 12% | either |
| April | +0.6 | 12% | 10% | either |
| May | +0.4 | 13% | 10% | either |
| June | +0.1 | 11% | 8% | either |
| July | −1.3 | 15% | 7% | either |
| August | −1.0 | 13% | 7% | either |
| September | −0.1 | 11% | 8% | either |
| October | −2.8 | 16% | 6% | Arzal → Tréméreuc |
| November | −3.1 | 18% | 7% | Arzal → Tréméreuc |
| December | −4.0 | 19% | 7% | Arzal → Tréméreuc |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | S | +2.2 |
| 25–50 | SE | +3.3 |
| 50–76 | SE | +2.1 |
| 76–101 | SW | −1.0 |
| 101–126 | S | +0.1 |
| 126–151 | S | −0.5 |
| 151–176 | SW | −2.0 |
| 176–201 | SW | −1.9 |
| 201–226 | SW | −2.5 |
| 226–233 | W | −4.0 |
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.