35: which way and when to ride
The best month for 35 is September: 78% 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 | 2% | 19% | 44 | 2 °C | 0% | 98% | 8.5 † |
| February | 6% | 16% | 33 | 3 °C | 0% | 93% | 10.0 † |
| March | 29% | 20% | 38 | 8 °C | 0% | 67% | 11.7 |
| April | 59% | 24% | 42 | 13 °C | 0% | 30% | 13.7 |
| May | 66% | 31% | 70 | 17 °C | 0% | 6% | 15.4 |
| June | 68% | 29% | 70 | 22 °C | 3% | 0% | 16.4 |
| July | 64% | 29% | 76 | 24 °C | 8% | 0% | 16.0 |
| August | 65% | 28% | 79 | 23 °C | 8% | 0% | 14.5 |
| September | 78% | 21% | 56 | 18 °C | 0% | 2% | 12.5 |
| October | 58% | 19% | 45 | 12 °C | 0% | 30% | 10.6 † |
| November | 15% | 17% | 41 | 6 °C | 0% | 82% | 8.9 † |
| December | 2% | 16% | 44 | 3 °C | 0% | 98% | 8.1 † |
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 Plzeň → near Klášterec nad Ohří, km/h | Headwind > 15 km/h, Plzeň → near Klášterec nad Ohří | Headwind > 15 km/h, near Klášterec nad Ohří → Plzeň | Better way |
|---|---|---|---|---|
| January | +0.2 | 5% | 5% | either |
| February | −0.2 | 5% | 4% | either |
| March | −1.1 | 6% | 4% | either |
| April | −1.8 | 6% | 2% | either |
| May | −1.5 | 6% | 3% | either |
| June | −1.7 | 5% | 1% | either |
| July | −1.7 | 4% | 1% | either |
| August | −0.3 | 2% | 1% | either |
| September | −0.5 | 4% | 2% | either |
| October | +0.5 | 3% | 3% | either |
| November | +1.0 | 3% | 3% | either |
| December | +1.1 | 3% | 5% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | NW | −1.3 |
| 25–51 | N | −0.7 |
| 51–76 | NE | +1.2 |
| 76–102 | N | −0.1 |
| 102–124 | NW | −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.