North-South Route: which way and when to ride
The best month for North-South Route is September: 62% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.5 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 | 3% | 24% | 97 | 1 °C | 0% | 96% | 8.9 † |
| February | 12% | 25% | 79 | 3 °C | 0% | 87% | 10.2 † |
| March | 28% | 30% | 105 | 7 °C | 0% | 67% | 11.8 |
| April | 43% | 33% | 121 | 11 °C | 0% | 43% | 13.5 |
| May | 44% | 47% | 167 | 14 °C | 0% | 24% | 15.0 |
| June | 48% | 49% | 171 | 19 °C | 2% | 6% | 15.8 |
| July | 49% | 47% | 177 | 21 °C | 4% | 2% | 15.5 |
| August | 55% | 42% | 187 | 21 °C | 3% | 3% | 14.2 |
| September | 62% | 34% | 142 | 17 °C | 0% | 10% | 12.5 |
| October | 53% | 27% | 137 | 12 °C | 0% | 33% | 10.8 † |
| November | 19% | 28% | 132 | 6 °C | 0% | 77% | 9.3 † |
| December | 3% | 27% | 111 | 2 °C | 0% | 96% | 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 Basel → Chiasso, km/h | Headwind > 15 km/h, Basel → Chiasso | Headwind > 15 km/h, Chiasso → Basel | Better way |
|---|---|---|---|---|
| January | +1.3 | 0% | 0% | either |
| February | +0.8 | 0% | 0% | either |
| March | +0.9 | 0% | 1% | either |
| April | +0.5 | 0% | 0% | either |
| May | +0.7 | 0% | 0% | either |
| June | +0.6 | 0% | 0% | either |
| July | +1.0 | 0% | 0% | either |
| August | +0.8 | 0% | 0% | either |
| September | +0.5 | 0% | 0% | either |
| October | +0.1 | 0% | 0% | either |
| November | +0.6 | 0% | 0% | either |
| December | +1.0 | 0% | 0% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–26 | SE | +1.0 |
| 26–51 | SE | +0.8 |
| 51–76 | S | +1.3 |
| 76–101 | SE | +1.5 |
| 101–127 | SE | +2.9 |
| 127–151 | E | +0.2 |
| 151–176 | S | +1.3 |
| 176–202 | S | +1.6 |
| 202–227 | SE | −0.1 |
| 227–253 | SE | −0.3 |
| 253–278 | SE | −0.8 |
| 278–303 | SW | −1.1 |
| 303–328 | S | −0.6 |
| 328–356 | SE | −0.1 |
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.