Østersøruten: which way and when to ride
The best month for Østersøruten is September: 78% of days were dry with highs of 10–30 °C. In September the wind barely favours either direction — on average 0.1 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% | 23% | 60 | 4 °C | 0% | 98% | 7.7 † |
| February | 2% | 19% | 46 | 4 °C | 0% | 98% | 9.6 † |
| March | 14% | 18% | 40 | 7 °C | 0% | 84% | 11.7 |
| April | 52% | 20% | 39 | 11 °C | 0% | 41% | 14.0 |
| May | 74% | 23% | 55 | 16 °C | 0% | 5% | 16.1 |
| June | 77% | 23% | 63 | 19 °C | 0% | 0% | 17.4 |
| July | 72% | 28% | 76 | 21 °C | 1% | 0% | 16.8 |
| August | 73% | 27% | 77 | 21 °C | 0% | 0% | 14.9 |
| September | 78% | 22% | 58 | 18 °C | 0% | 0% | 12.6 |
| October | 66% | 23% | 66 | 13 °C | 0% | 13% | 10.3 † |
| November | 21% | 22% | 54 | 8 °C | 0% | 71% | 8.3 † |
| December | 3% | 21% | 58 | 5 °C | 0% | 95% | 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 Padborg → near Flensburg, km/h | Headwind > 15 km/h, Padborg → near Flensburg | Headwind > 15 km/h, near Flensburg → Padborg | Better way |
|---|---|---|---|---|
| January | +0.3 | 19% | 20% | either |
| February | +0.1 | 19% | 19% | either |
| March | +0.1 | 18% | 19% | either |
| April | +0.1 | 16% | 16% | either |
| May | +0.1 | 17% | 17% | either |
| June | +0.2 | 16% | 16% | either |
| July | +0.2 | 16% | 17% | either |
| August | +0.2 | 15% | 16% | either |
| September | +0.1 | 18% | 18% | either |
| October | +0.1 | 18% | 19% | either |
| November | +0.2 | 17% | 18% | either |
| December | +0.3 | 18% | 19% | either |
Stages
The route is split into 7 stages of about 100–150 km between towns; each stage has its own page.
| Stage | km | Best month | Tailwind Padborg → near Flensburg in September, km/h |
|---|---|---|---|
| 1. Padborg → Svendborg | 128 | September | +5.0 |
| 2. Svendborg → Maribo | 134 | September | +1.1 |
| 3. Maribo → Stege | 119 | September | +5.6 |
| 4. Stege → Klinteby Frihed | 129 | September | −0.9 |
| 5. Klinteby Frihed → Svendborg | 130 | September | −4.6 |
| 6. Svendborg → Fredericia | 134 | September | −0.8 |
| 7. Fredericia → near Flensburg | 127 | June | −4.1 |
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.