The Vipava valley: fast roads and the wind that decides your day

The Vipava valley is a wedge of flat, warm, vine-covered land that runs south-east from Nova Gorica towards the Karst, walled in on its north side by the limestone plateaus of Trnovski gozd and Nanos. The valley floor is where Slovenia's fastest road riding is; the plateaus are where its most serious climbs south of the Alps are; and between them, a few times a month in winter, comes the burja.

The tourist board's line is that the valley "has just one cycling season: the entire year", and the climate numbers back that up. What they do not say in the same sentence is that on the days the burja blows, the season closes for the day. That is the whole trick to riding here: the roads are simple, the wind is not.

The valley floor

Between Vipava and Nova Gorica the valley is roughly 30 km long and never more than a few kilometres wide, with the H4 expressway taking the through traffic and leaving the old road and the village lanes to bikes. The tourist board's signed road route through the lower valley, the Branica valley loop, is the template: 46.8 km from Vipava through Podnanos, Štanjel, Goče, Branik and Dornberk and back via Ajdovščina, with 504 m of climbing and an altitude range of 57–237 m. It is rated easy and it is — a fast, rolling day through vineyards on roads where the only real rises are the short pulls up to hilltop villages like Goče and Vipavski Križ.

This is the terrain the pros come for. The tourist board notes that the valley's roads have been used twice by the Giro d'Italia and several times by the Tour of Slovenia, and if you have watched those stages you will know why: flat, exposed and fast into a headwind, then a sudden wall up to a village on a spur. Riding it well is about group discipline more than fitness, and if you are here with friends, group riding skills pay for themselves on the exposed sections.

Up: Nanos and the Predmeja road

The north wall of the valley is where the climbing is, and there are two roads that matter.

• Nanos. The tourist board's Nanos route starts at the Lanthieri mansion in Vipava, at 98 m, and reaches the plateau at 1,240 m: 44.1 km and 1,392 m of climbing in a loop, rated hard. The ascent proper leaves the main road past Podnanos and is described as 8 km of steep road — asphalt to the mountain hut, gravel on the plateau beyond. On a road bike, the asphalt section to the hut is the climb; the rest wants wider tyres. It is one of the biggest single ascents in the country outside the Alps and it starts from almost sea level.
• Predmeja and the Gora plateau. The other road climbs from Ajdovščina, at 106 m, up the escarpment through Lokavec to Predmeja and on to the Gora plateau at 903 m. The tourist board's loop over it is 36.2 km with 1,067 m of climbing through Predmeja, Čaven, Col, Kovk and Sinji vrh, rated hard and timed at three hours. The Predmeja hill itself is the reason: a long, unrelenting ascent up a wall you can see from the whole valley, with hairpins and short rock tunnels near the top. Once up, the plateau is a different country — beech forest, meadows and cold air.

Both climbs are long enough to pace with numbers. A steady power-based pacing approach works well because the gradients are consistent; the mistake people make on Predmeja is going too hard in the first 3 km, where the valley heat is still with you, and blowing up in the forest where the gradient does not ease.

Two climates, 850 metres apart

ARSO has stations at both ends of the climb: Bilje on the valley floor near Nova Gorica at 55 m, and Nanos–Abram on the plateau at 905 m. The pair is the clearest illustration in Slovenia of why you carry a jacket on a hot day.

So: the valley is ridable in every month, with a January mean daily maximum of 7.9 °C at Bilje and next to no snow. The plateaus are a May-to-October proposition, and even in July the top of Nanos is 6–7 degrees cooler than Vipava. The tourist board's own advice is the right one — in winter ride the southern hills and the Karst side, in summer go up into the forest to escape the heat — and Bilje's 30 days a year above 30 °C is the reason the second half of that matters.

The burja

The burja is a north-easterly downslope wind that falls off the Trnovo and Nanos plateaus into the valley when high pressure sits over central Europe, most often in winter. It is the strongest wind in Slovenia and the Vipava valley is where it is strongest. Meteorological reviews of the bora describe its defining property as extreme gustiness on timescales of seconds, and that is exactly what makes it dangerous on a bicycle: a mean speed you could lean into becomes a gust that moves you a metre sideways.

The traffic information service measures it continuously on the exposed sections of the H4 and A1 and publishes a four-level scale:

Our rule: if promet.si is showing any burja level at all on the H4, the valley floor and the plateaus are both off. The road through Rebrnice, the expressway section climbing out of the valley towards Razdrto, and the open stretch between Ajdovščina and Vipava are the most exposed; the Branica valley on the south side is partly sheltered and is the one place locals will point you to on a marginal day. Check the gust forecast, not the mean — reading a wind forecast for cyclists covers why — and if the forecast says north-easterly and rising, ride in the morning; in our experience the burja tends to build through the day.

Putting it together

Ajdovščina or Vipava are the bases: both are at the foot of the two big climbs and on the flat loops. Nova Gorica has the railway station and puts Brda and the Soča valley within reach as well. A good four days: the Branica loop to learn the valley, Predmeja and the Gora plateau, Nanos, and a day across the Karst to Štanjel and back. Save them in Moveee's route builder to see the profiles side by side, and if a burja day takes one of them away, the Predmeja climb rides well in Moveee Indoor while you wait for the wind to drop.

For where the valley sits in the country, see our guide to cycling in Slovenia; for the plateaus themselves, mountain pass route planning applies to Nanos even though it is not, strictly, a pass. The honest summary: the fastest flat roads in Slovenia, two of its hardest climbs, and a wind that will cancel a day without warning. Plan the week with a spare day in it.