Nasjonal sykkelrute 2: which way and when to ride
The best month for Nasjonal sykkelrute 2 is June: 64% of days were dry with highs of 10–30 °C. In June 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% | 29% | 100 | -3 °C | 0% | 100% | 6.8 † |
| February | 0% | 25% | 73 | -2 °C | 0% | 100% | 9.1 † |
| March | 4% | 22% | 69 | 2 °C | 0% | 96% | 11.6 |
| April | 23% | 22% | 57 | 7 °C | 0% | 76% | 14.4 |
| May | 49% | 31% | 84 | 12 °C | 0% | 39% | 17.0 |
| June | 64% | 34% | 100 | 16 °C | 0% | 7% | 18.7 |
| July | 60% | 39% | 125 | 18 °C | 0% | 1% | 17.9 |
| August | 61% | 39% | 124 | 16 °C | 0% | 2% | 15.6 |
| September | 55% | 31% | 121 | 13 °C | 0% | 25% | 12.7 |
| October | 18% | 30% | 110 | 7 °C | 0% | 77% | 10.0 † |
| November | 2% | 29% | 110 | 2 °C | 0% | 97% | 7.5 † |
| December | 0% | 31% | 102 | -2 °C | 0% | 100% | 6.0 † |
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 Porsgrunn → near Geilo, km/h | Headwind > 15 km/h, Porsgrunn → near Geilo | Headwind > 15 km/h, near Geilo → Porsgrunn | Better way |
|---|---|---|---|---|
| January | −1.2 | 2% | 2% | either |
| February | −0.5 | 1% | 2% | either |
| March | −0.4 | 3% | 2% | either |
| April | −0.6 | 5% | 2% | either |
| May | +0.2 | 3% | 2% | either |
| June | +0.8 | 3% | 2% | either |
| July | +1.3 | 2% | 1% | either |
| August | +1.6 | 1% | 2% | either |
| September | +0.7 | 3% | 2% | either |
| October | +0.4 | 2% | 2% | either |
| November | −0.4 | 2% | 2% | either |
| December | −0.9 | 2% | 2% | either |
Along the route (sections of about 25 km)
| km | Heading | Tailwind in June, km/h |
|---|---|---|
| 0–12 | NW | +1.9 |
| 12–38 | NW | +0.9 |
| 38–63 | NW | +2.7 |
| 63–89 | W | 0.0 |
| 89–114 | W | −0.6 |
| 114–139 | W | −1.4 |
| 139–164 | NW | −0.4 |
| 164–189 | N | +1.2 |
| 189–215 | NE | +2.8 |
| 215–240 | NE | +2.9 |
| 240–265 | NE | +1.9 |
| 265–291 | N | +1.2 |
| 291–316 | NW | −0.8 |
| 316–338 | N | −0.2 |
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.