Mittelland Route (Romanshorn – Lausanne): which way and when to ride
The best month for Mittelland Route (Romanshorn – Lausanne) is September: 74% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.0 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 | 5% | 26% | 97 | 4 °C | 0% | 93% | 8.9 † |
| February | 17% | 26% | 73 | 6 °C | 0% | 80% | 10.2 † |
| March | 40% | 30% | 90 | 10 °C | 0% | 51% | 11.8 |
| April | 59% | 32% | 91 | 14 °C | 0% | 22% | 13.5 |
| May | 56% | 43% | 142 | 18 °C | 0% | 5% | 15.1 |
| June | 56% | 40% | 129 | 22 °C | 5% | 0% | 15.9 |
| July | 56% | 36% | 137 | 24 °C | 9% | 0% | 15.6 |
| August | 59% | 34% | 138 | 23 °C | 8% | 0% | 14.2 |
| September | 74% | 26% | 102 | 19 °C | 0% | 1% | 12.5 |
| October | 66% | 25% | 92 | 14 °C | 0% | 16% | 10.8 † |
| November | 26% | 27% | 98 | 8 °C | 0% | 67% | 9.2 † |
| December | 5% | 31% | 111 | 4 °C | 0% | 93% | 8.5 † |
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 Romanshorn → Lausanne, km/h | Headwind > 15 km/h, Romanshorn → Lausanne | Headwind > 15 km/h, Lausanne → Romanshorn | Better way |
|---|---|---|---|---|
| January | −2.2 | 7% | 1% | Lausanne → Romanshorn |
| February | −1.3 | 6% | 3% | either |
| March | −1.1 | 8% | 4% | either |
| April | +0.3 | 4% | 3% | either |
| May | −0.4 | 4% | 3% | either |
| June | 0.0 | 2% | 2% | either |
| July | −1.3 | 3% | 1% | either |
| August | −1.3 | 2% | 0% | either |
| September | 0.0 | 3% | 2% | either |
| October | −0.5 | 3% | 1% | either |
| November | −1.8 | 4% | 1% | either |
| December | −2.6 | 6% | 1% | Lausanne → Romanshorn |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | SW | +0.3 |
| 25–50 | W | −1.0 |
| 50–76 | W | −1.2 |
| 76–101 | SW | −0.3 |
| 101–126 | W | −0.3 |
| 126–151 | W | −0.2 |
| 151–176 | SW | +0.7 |
| 176–201 | SW | +0.2 |
| 201–226 | W | +0.1 |
| 226–252 | SW | +0.2 |
| 252–277 | SW | +0.3 |
| 277–302 | SW | +0.1 |
| 302–327 | SW | −0.3 |
| 327–352 | SW | +0.2 |
| 352–379 | SE | +1.1 |
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.