Bornholm rundt: clockwise or anticlockwise, and when to ride
The best month for Bornholm rundt is June: 82% of days were dry in riding hours with highs of 10–30 °C. In June the wind barely favours either way round — under 2 km/h on average (ERA5 2006–2025, daytime 9:00–18:00).
This route is a loop: the two directions are clockwise and anticlockwise.
Weather by month
| Month | Good days | Rain days ≥ 1 mm | Rain, mm | Avg high | Days ≥ 30 °C | Days < 10 °C | Daylight, h |
|---|---|---|---|---|---|---|---|
| January | 0% | 22% | 59 | 3 °C | 0% | 99% | 7.7 † |
| February | 1% | 18% | 44 | 3 °C | 0% | 99% | 9.6 † |
| March | 6% | 16% | 36 | 5 °C | 0% | 93% | 11.7 |
| April | 33% | 13% | 28 | 9 °C | 0% | 65% | 14.0 |
| May | 71% | 16% | 40 | 13 °C | 0% | 16% | 16.1 |
| June | 82% | 18% | 48 | 18 °C | 0% | 0% | 17.4 |
| July | 76% | 24% | 66 | 20 °C | 0% | 0% | 16.9 |
| August | 76% | 24% | 70 | 20 °C | 0% | 0% | 15.0 |
| September | 82% | 18% | 51 | 17 °C | 0% | 0% | 12.6 |
| October | 64% | 21% | 65 | 12 °C | 0% | 19% | 10.3 † |
| November | 19% | 24% | 59 | 8 °C | 0% | 75% | 8.2 † |
| December | 2% | 25% | 58 | 5 °C | 0% | 98% | 7.2 † |
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, clockwise, km/h | Headwind > 15 km/h, clockwise | Headwind > 15 km/h, anticlockwise | Better way |
|---|---|---|---|---|
| January | −0.9 | 23% | 20% | either |
| February | −0.6 | 22% | 19% | either |
| March | −0.3 | 18% | 18% | either |
| April | +0.4 | 15% | 17% | either |
| May | +0.2 | 14% | 15% | either |
| June | +0.3 | 13% | 14% | either |
| July | +0.2 | 14% | 14% | either |
| August | 0.0 | 14% | 14% | either |
| September | −0.2 | 18% | 18% | either |
| October | −0.7 | 21% | 18% | either |
| November | −1.2 | 21% | 18% | either |
| December | −1.2 | 23% | 19% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in June, km/h |
|---|---|---|
| 0–25 | N | +4.4 |
| 25–50 | SE | +2.4 |
| 50–75 | S | −1.3 |
| 75–103 | NW | −4.0 |
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.