Graubünden Route: which way and when to ride
The best month for Graubünden Route is August: 51% of days were dry with highs of 10–30 °C. In August the wind barely favours either direction — on average 1.3 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 | 0% | 22% | 77 | -4 °C | 0% | 100% | 8.9 † |
| February | 1% | 23% | 63 | -2 °C | 0% | 99% | 10.2 † |
| March | 3% | 28% | 83 | 1 °C | 0% | 97% | 11.8 |
| April | 14% | 35% | 100 | 5 °C | 0% | 82% | 13.5 |
| May | 24% | 57% | 148 | 9 °C | 0% | 55% | 15.0 |
| June | 39% | 57% | 152 | 15 °C | 0% | 16% | 15.8 |
| July | 45% | 53% | 143 | 17 °C | 0% | 8% | 15.5 |
| August | 51% | 47% | 155 | 16 °C | 0% | 10% | 14.2 |
| September | 50% | 36% | 115 | 12 °C | 0% | 30% | 12.5 |
| October | 30% | 26% | 120 | 8 °C | 0% | 67% | 10.8 † |
| November | 3% | 26% | 115 | 1 °C | 0% | 97% | 9.3 † |
| December | 0% | 25% | 89 | -3 °C | 0% | 100% | 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 Nauders → Martina, km/h | Headwind > 15 km/h, Nauders → Martina | Headwind > 15 km/h, Martina → Nauders | Better way |
|---|---|---|---|---|
| January | +1.2 | 0% | 0% | either |
| February | +0.5 | 0% | 0% | either |
| March | −0.2 | 0% | 0% | either |
| April | −0.7 | 0% | 0% | either |
| May | −0.9 | 0% | 0% | either |
| June | −1.3 | 0% | 0% | either |
| July | −1.4 | 0% | 0% | either |
| August | −1.3 | 0% | 0% | either |
| September | −0.8 | 0% | 0% | either |
| October | −0.3 | 0% | 0% | either |
| November | +0.5 | 0% | 0% | either |
| December | +1.3 | 0% | 0% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in August, km/h |
|---|---|---|
| 0–25 | SW | −1.5 |
| 25–50 | SW | −1.1 |
| 50–76 | SW | −0.6 |
| 76–101 | NW | −1.7 |
| 101–127 | W | −2.0 |
| 127–150 | NE | −1.2 |
| 150–175 | SW | −1.1 |
| 175–200 | SW | −1.2 |
| 200–225 | S | −0.3 |
| 225–250 | SW | −2.1 |
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.