P'tites Routes du Soleil, stage 1: Thonon-les-Bains → Rumilly
On stage 1 (Thonon-les-Bains → Rumilly, 138 km) the best month is September: 73% of days were dry with highs of 10–30 °C; the wind barely favours either direction (0.7 km/h on average; ERA5 2006–2025, 9:00–18:00).
← P'tites Routes du Soleil (Whole route)
Weather by month
| Month | Good days | Rain days ≥ 1 mm | Rain, mm | Avg high | Days ≥ 30 °C | Days < 10 °C | Daylight, h |
|---|---|---|---|---|---|---|---|
| January | 7% | 29% | 130 | 4 °C | 0% | 92% | 9.0 † |
| February | 21% | 26% | 97 | 6 °C | 0% | 77% | 10.3 † |
| March | 43% | 31% | 121 | 10 °C | 0% | 49% | 11.8 |
| April | 59% | 33% | 106 | 15 °C | 0% | 19% | 13.5 |
| May | 54% | 46% | 168 | 17 °C | 0% | 6% | 14.9 |
| June | 56% | 41% | 137 | 22 °C | 4% | 0% | 15.8 |
| July | 58% | 36% | 144 | 24 °C | 8% | 0% | 15.4 |
| August | 63% | 30% | 127 | 23 °C | 8% | 0% | 14.1 |
| September | 73% | 27% | 117 | 19 °C | 0% | 1% | 12.5 |
| October | 70% | 24% | 112 | 15 °C | 0% | 12% | 10.8 † |
| November | 32% | 30% | 135 | 9 °C | 0% | 60% | 9.4 † |
| December | 7% | 32% | 154 | 5 °C | 0% | 92% | 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 Thonon-les-Bains → Rumilly, km/h | Headwind > 15 km/h, Thonon-les-Bains → Rumilly | Headwind > 15 km/h, Rumilly → Thonon-les-Bains | Better way |
|---|---|---|---|---|
| January | −0.5 | 0% | 0% | either |
| February | −0.3 | 1% | 1% | either |
| March | +0.2 | 1% | 2% | either |
| April | +0.8 | 1% | 1% | either |
| May | +0.4 | 0% | 2% | either |
| June | +0.4 | 0% | 1% | either |
| July | −0.1 | 0% | 0% | either |
| August | 0.0 | 0% | 0% | either |
| September | +0.7 | 0% | 1% | either |
| October | +0.1 | 0% | 1% | either |
| November | −0.4 | 0% | 1% | either |
| December | −0.8 | 0% | 0% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | S | +2.1 |
| 25–50 | SW | +0.1 |
| 50–76 | SW | +0.2 |
| 76–101 | SW | −0.5 |
| 101–126 | S | +1.0 |
| 126–138 | S | +1.4 |
Other stages
- Thonon-les-Bains → Rumilly 138 km
- Rumilly → Saint-Christophe-sur-Guiers 119 km
- Saint-Christophe-sur-Guiers → Villard-de-Lans 96 km
- Villard-de-Lans → near Veynes 120 km
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.