Rhone Route - Andermatt-Geneva (Chancy): which way and when to ride
The best month for Rhone Route - Andermatt-Geneva (Chancy) is September: 60% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.6 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 | 2% | 28% | 122 | -1 °C | 0% | 98% | 9.0 † |
| February | 7% | 27% | 90 | 1 °C | 0% | 92% | 10.3 † |
| March | 18% | 31% | 117 | 4 °C | 0% | 80% | 11.8 |
| April | 33% | 34% | 111 | 9 °C | 0% | 57% | 13.5 |
| May | 38% | 48% | 162 | 12 °C | 0% | 37% | 15.0 |
| June | 49% | 48% | 145 | 17 °C | 1% | 11% | 15.8 |
| July | 54% | 44% | 157 | 19 °C | 2% | 4% | 15.4 |
| August | 58% | 39% | 150 | 19 °C | 2% | 6% | 14.2 |
| September | 60% | 33% | 122 | 15 °C | 0% | 17% | 12.5 |
| October | 46% | 27% | 118 | 11 °C | 0% | 43% | 10.8 † |
| November | 15% | 31% | 135 | 4 °C | 0% | 81% | 9.3 † |
| December | 2% | 31% | 143 | 0 °C | 0% | 97% | 8.6 † |
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 Andermatt → Genève (Chancy), km/h | Headwind > 15 km/h, Andermatt → Genève (Chancy) | Headwind > 15 km/h, Genève (Chancy) → Andermatt | Better way |
|---|---|---|---|---|
| January | 0.0 | 1% | 0% | either |
| February | −0.2 | 1% | 1% | either |
| March | −0.5 | 1% | 1% | either |
| April | −0.4 | 1% | 1% | either |
| May | −0.7 | 0% | 1% | either |
| June | −1.0 | 0% | 1% | either |
| July | −1.5 | 0% | 0% | either |
| August | −1.3 | 0% | 0% | either |
| September | −0.6 | 0% | 1% | either |
| October | −0.2 | 0% | 0% | either |
| November | 0.0 | 0% | 0% | either |
| December | 0.0 | 0% | 0% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | SW | 0.0 |
| 25–50 | SW | +0.2 |
| 50–75 | SW | +0.1 |
| 75–101 | W | −0.2 |
| 101–126 | W | −1.0 |
| 126–151 | SW | −0.8 |
| 151–176 | W | −0.5 |
| 176–202 | NW | −2.8 |
| 202–227 | NW | −3.0 |
| 227–252 | W | −1.6 |
| 252–278 | W | +0.1 |
| 278–303 | SW | +0.4 |
| 303–328 | SW | +0.9 |
| 328–345 | SW | +0.2 |
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.