Stary Kolejowy Szlak: which way and when to ride
The best month for Stary Kolejowy Szlak is September: 79% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.6 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 | 1% | 22% | 60 | 2 °C | 0% | 98% | 8.0 † |
| February | 4% | 20% | 44 | 3 °C | 0% | 96% | 9.7 † |
| March | 25% | 21% | 42 | 7 °C | 0% | 71% | 11.7 |
| April | 59% | 21% | 38 | 13 °C | 0% | 32% | 13.9 |
| May | 72% | 27% | 60 | 17 °C | 0% | 4% | 15.9 |
| June | 70% | 27% | 66 | 21 °C | 3% | 0% | 17.0 |
| July | 66% | 30% | 99 | 23 °C | 4% | 0% | 16.6 |
| August | 67% | 29% | 80 | 23 °C | 4% | 0% | 14.8 |
| September | 79% | 20% | 52 | 19 °C | 0% | 0% | 12.6 |
| October | 61% | 23% | 56 | 13 °C | 0% | 24% | 10.4 † |
| November | 18% | 21% | 48 | 7 °C | 0% | 78% | 8.5 † |
| December | 3% | 22% | 49 | 3 °C | 0% | 96% | 7.5 † |
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 Budzistowo → Piła, km/h | Headwind > 15 km/h, Budzistowo → Piła | Headwind > 15 km/h, Piła → Budzistowo | Better way |
|---|---|---|---|---|
| January | −0.3 | 10% | 10% | either |
| February | +0.3 | 9% | 12% | either |
| March | +1.4 | 8% | 11% | either |
| April | +2.7 | 7% | 14% | Budzistowo → Piła |
| May | +1.9 | 8% | 12% | either |
| June | +3.6 | 4% | 13% | Budzistowo → Piła |
| July | +4.2 | 3% | 13% | Budzistowo → Piła |
| August | +1.6 | 4% | 8% | either |
| September | +0.6 | 7% | 9% | either |
| October | −1.2 | 10% | 8% | either |
| November | −2.2 | 9% | 7% | Piła → Budzistowo |
| December | −1.0 | 10% | 9% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | SE | +2.1 |
| 25–50 | SE | +1.4 |
| 50–77 | SE | −0.4 |
| 77–104 | S | −2.4 |
| 104–134 | SE | +1.4 |
| 134–159 | SE | +0.8 |
| 159–187 | SE | +1.4 |
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.