Route des Grandes Alpes à vélo - Tracé principal, stage 4: Guillestre → Péone
On stage 4 (Guillestre → Péone, 116 km) the best month is August: 71% of days were dry with highs of 10–30 °C; the wind barely favours either direction (1.0 km/h on average; ERA5 2006–2025, 9:00–18:00).
← Route des Grandes Alpes à vélo - Tracé principal (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 | 1% | 18% | 74 | -1 °C | 0% | 99% | 9.2 † |
| February | 3% | 20% | 68 | 0 °C | 0% | 97% | 10.4 † |
| March | 5% | 23% | 90 | 2 °C | 0% | 95% | 11.8 |
| April | 11% | 35% | 96 | 6 °C | 0% | 85% | 13.4 |
| May | 29% | 48% | 124 | 10 °C | 0% | 49% | 14.8 |
| June | 48% | 51% | 116 | 16 °C | 0% | 7% | 15.5 |
| July | 66% | 34% | 68 | 19 °C | 0% | 0% | 15.2 |
| August | 71% | 29% | 63 | 19 °C | 0% | 1% | 14.0 |
| September | 66% | 29% | 74 | 15 °C | 0% | 10% | 12.4 |
| October | 50% | 24% | 108 | 11 °C | 0% | 41% | 10.9 † |
| November | 10% | 24% | 125 | 4 °C | 0% | 90% | 9.5 † |
| December | 2% | 19% | 97 | -1 °C | 0% | 98% | 8.9 † |
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 Guillestre → Péone, km/h | Headwind > 15 km/h, Guillestre → Péone | Headwind > 15 km/h, Péone → Guillestre | Better way |
|---|---|---|---|---|
| January | +2.3 | 0% | 0% | Guillestre → Péone |
| February | +1.5 | 0% | 0% | either |
| March | +1.2 | 0% | 1% | either |
| April | 0.0 | 0% | 1% | either |
| May | −0.1 | 0% | 1% | either |
| June | −1.1 | 0% | 0% | either |
| July | −0.8 | 0% | 0% | either |
| August | −1.0 | 0% | 0% | either |
| September | −0.8 | 0% | 0% | either |
| October | −0.5 | 0% | 0% | either |
| November | +1.1 | 0% | 0% | either |
| December | +2.2 | 0% | 0% | Guillestre → Péone |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in August, km/h |
|---|---|---|
| 412–437 | S | −0.9 |
| 437–462 | S | −3.5 |
| 462–487 | SE | +0.6 |
| 487–513 | S | −2.0 |
| 513–528 | E | +2.1 |
Other stages
- Thonon-les-Bains → Beaufort 128 km
- Beaufort → Modane 151 km
- Modane → Guillestre 134 km
- Guillestre → Péone 116 km
- Péone → Nice 168 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.