Intercity Bike Routes - IBR: which way and when to ride
The best month for Intercity Bike Routes - IBR is October: 72% of days were dry with highs of 10–30 °C. In October the wind barely favours either direction — on average 0.8 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 | 14% | 25% | 93 | 5 °C | 0% | 84% | 9.2 † |
| February | 27% | 28% | 90 | 7 °C | 0% | 69% | 10.4 † |
| March | 44% | 31% | 105 | 10 °C | 0% | 46% | 11.8 |
| April | 59% | 35% | 100 | 15 °C | 0% | 15% | 13.4 |
| May | 56% | 43% | 136 | 19 °C | 0% | 2% | 14.8 |
| June | 54% | 37% | 97 | 24 °C | 10% | 0% | 15.5 |
| July | 52% | 29% | 83 | 26 °C | 22% | 0% | 15.2 |
| August | 55% | 27% | 79 | 26 °C | 20% | 0% | 14.0 |
| September | 68% | 29% | 103 | 21 °C | 3% | 2% | 12.4 |
| October | 72% | 21% | 93 | 16 °C | 0% | 12% | 10.9 † |
| November | 45% | 26% | 115 | 11 °C | 0% | 43% | 9.5 † |
| December | 15% | 24% | 104 | 6 °C | 0% | 81% | 8.8 † |
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 Banja Luka → Bosansko Grahovo, km/h | Headwind > 15 km/h, Banja Luka → Bosansko Grahovo | Headwind > 15 km/h, Bosansko Grahovo → Banja Luka | Better way |
|---|---|---|---|---|
| January | +0.2 | 2% | 2% | either |
| February | +0.6 | 4% | 4% | either |
| March | +0.8 | 5% | 5% | either |
| April | +1.0 | 3% | 3% | either |
| May | +0.6 | 2% | 2% | either |
| June | +1.3 | 1% | 2% | either |
| July | +2.2 | 1% | 1% | Banja Luka → Bosansko Grahovo |
| August | +2.6 | 1% | 1% | Banja Luka → Bosansko Grahovo |
| September | +2.0 | 1% | 2% | Banja Luka → Bosansko Grahovo |
| October | +0.8 | 2% | 2% | either |
| November | −0.4 | 2% | 1% | either |
| December | +0.2 | 3% | 2% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in October, km/h |
|---|---|---|
| 0–25 | SW | +1.8 |
| 25–34 | NE | −1.8 |
| 34–59 | SW | +1.0 |
| 59–84 | SW | +0.9 |
| 84–109 | W | +0.8 |
| 109–134 | W | +0.8 |
| 134–160 | S | +1.0 |
| 160–171 | SE | −0.3 |
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.