From Pamplona · 42.81° N · 1.65° W
Getaways from Pamplona for 15 August: Ordesa first thing, Urbión, canyons at Aínsa, the shade of Irati and the coast of Getaria, Hondarribia and Urdaibai.
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In summer you only go up to the Pradera on the Torla bus, and the August long weekend is when the valley's 1,800-person limit is reached soonest. The first departure is at 6:00: with the first bus you walk to the Cola de Caballo in the cool and without people.
At about 1,700 metres, the Urbión glacial lagoons have in August the temperature the Ribera lacks. Some weekends access to the Laguna Negra is regulated: call the Casa del Parque first, and go up early, before the track fills.

August is the month of the Guara canyons, with the water already warm and the sun high in the gorge. Do the guided canyon in the morning and leave Añisclo for the other day, first thing. At night the Plaza Mayor in Aínsa stays cool.

When Pamplona goes above 30 degrees, you walk under the Irati beeches in short sleeves without sweating. The 10 km to the Cubo Waterfall are almost all in shade. In August the Casas de Irati car park fills: arrive before ten.

Urdaibai is at its best from May to September, with Laida beach and the canoe along the estuary. In July and August the climb to Gaztelugatxe usually has controlled access: book the free ticket from the Bizkaia provincial council and go up first thing.

From April to October you eat on the terrace above the harbour and end the day at Zarautz beach. In August the Gipuzkoa coast is full for Donostia's Semana Grande: park in Getaria before eleven and book the grill.

In summer the motor boat crosses to Hendaye until late and the Jaizkibel boat sails on the days in its calendar. With small children, Hondarribia beach, inside the bay, has hardly any waves. 15 August is also a holiday in France: Hendaye will be full.

For those who do not fear crowds: in July and August there are traffic jams towards Cap Ferret and the Pilat dune is climbed in a queue, because 15 August is a holiday in France too. In return, the oyster huts open every day. Book the hotel months ahead.
Questions
No: in summer access to the Pradera is by the shuttle bus from Torla. The Torla car park is free and the return ticket costs €6.
Much less than in Pamplona. The forest gives shade along almost the whole way to the Cubo Waterfall and the stream water is cold.
On controlled-access days, yes. They are set each year by the Bizkaia provincial council and in July and August there are usually many.
If you arrive early and book lunch, yes. It is the week of Donostia's Semana Grande and holiday in France, with the coast full.
Geocaliahttps://www.geocalia.com/en/spain/navarre/pamplona/getaways/august-long-weekend