12 - Otavská: which way and when to ride
The best month for 12 - Otavská is September: 73% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.7 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 | 2% | 23% | 56 | 1 °C | 0% | 98% | 8.6 † |
| February | 7% | 18% | 40 | 3 °C | 0% | 92% | 10.1 † |
| March | 31% | 23% | 49 | 8 °C | 0% | 66% | 11.7 |
| April | 58% | 27% | 53 | 13 °C | 0% | 29% | 13.7 |
| May | 60% | 38% | 97 | 17 °C | 0% | 7% | 15.3 |
| June | 62% | 35% | 103 | 21 °C | 3% | 1% | 16.2 |
| July | 59% | 36% | 100 | 23 °C | 6% | 0% | 15.8 |
| August | 62% | 32% | 99 | 23 °C | 7% | 0% | 14.4 |
| September | 73% | 26% | 73 | 18 °C | 0% | 4% | 12.5 |
| October | 59% | 20% | 51 | 13 °C | 0% | 30% | 10.7 † |
| November | 19% | 18% | 48 | 6 °C | 0% | 79% | 9.0 † |
| December | 2% | 20% | 50 | 3 °C | 0% | 97% | 8.2 † |
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 near Kovářov → near Zwiesel, km/h | Headwind > 15 km/h, near Kovářov → near Zwiesel | Headwind > 15 km/h, near Zwiesel → near Kovářov | Better way |
|---|---|---|---|---|
| January | −4.3 | 13% | 1% | near Zwiesel → near Kovářov |
| February | −2.8 | 10% | 2% | near Zwiesel → near Kovářov |
| March | −1.7 | 10% | 3% | either |
| April | +0.5 | 5% | 3% | either |
| May | +0.6 | 4% | 3% | either |
| June | +0.1 | 3% | 1% | either |
| July | −1.6 | 5% | 0% | either |
| August | −1.4 | 3% | 0% | either |
| September | −0.7 | 4% | 1% | either |
| October | −2.2 | 6% | 1% | near Zwiesel → near Kovářov |
| November | −3.3 | 8% | 1% | near Zwiesel → near Kovářov |
| December | −4.7 | 10% | 1% | near Zwiesel → near Kovářov |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | SW | −0.5 |
| 25–50 | SW | −0.5 |
| 50–76 | W | −1.8 |
| 76–101 | SW | −1.4 |
| 101–126 | SW | −0.3 |
| 126–142 | SE | +0.8 |
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.