Green Velo - 04 Suwalszczyzna i Pojezierze Augustowskie: which way and when to ride
The best month for Green Velo - 04 Suwalszczyzna i Pojezierze Augustowskie is September: 79% of days were dry with highs of 10–30 °C. In September 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 | 0% | 22% | 48 | -1 °C | 0% | 100% | 7.9 † |
| February | 1% | 18% | 37 | 0 °C | 0% | 99% | 9.7 † |
| March | 18% | 18% | 35 | 6 °C | 0% | 79% | 11.7 |
| April | 55% | 22% | 40 | 12 °C | 0% | 36% | 14.0 |
| May | 71% | 26% | 63 | 18 °C | 0% | 5% | 15.9 |
| June | 69% | 28% | 70 | 22 °C | 3% | 0% | 17.1 |
| July | 62% | 34% | 98 | 23 °C | 5% | 0% | 16.6 |
| August | 68% | 27% | 82 | 23 °C | 5% | 0% | 14.8 |
| September | 79% | 19% | 52 | 18 °C | 0% | 3% | 12.6 |
| October | 50% | 21% | 52 | 11 °C | 0% | 40% | 10.4 † |
| November | 8% | 18% | 41 | 5 °C | 0% | 89% | 8.4 † |
| December | 1% | 18% | 44 | 1 °C | 0% | 99% | 7.4 † |
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 Wiżajny → near Augustów, km/h | Headwind > 15 km/h, Wiżajny → near Augustów | Headwind > 15 km/h, near Augustów → Wiżajny | Better way |
|---|---|---|---|---|
| January | −2.3 | 14% | 7% | near Augustów → Wiżajny |
| February | −1.7 | 13% | 8% | either |
| March | 0.0 | 10% | 10% | either |
| April | +1.4 | 7% | 12% | either |
| May | +1.4 | 7% | 10% | either |
| June | +1.6 | 5% | 9% | either |
| July | +1.3 | 5% | 8% | either |
| August | −0.7 | 6% | 5% | either |
| September | −0.8 | 9% | 8% | either |
| October | −2.4 | 14% | 7% | near Augustów → Wiżajny |
| November | −4.0 | 15% | 4% | near Augustów → Wiżajny |
| December | −3.4 | 15% | 6% | near Augustów → Wiżajny |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in September, km/h |
|---|---|---|
| 0–25 | S | −1.1 |
| 25–51 | SE | −0.1 |
| 51–76 | SE | +1.2 |
| 76–101 | S | −0.8 |
| 101–126 | SW | −2.4 |
| 126–140 | SW | −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.