From Tarragona · 41.12° N · 1.24° E
Three getaways with a night away and four day trips from Tarragona for 12 October, the Pilar and National Day: the Priorat vines as they begin to change colour, the Siurana reservoir, Guara and Añisclo in their autumn, the Parrizal without heat, the Codorníu cellars and the top of Montserrat.
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After the harvest, from October, the Priorat and Montsant vines begin to turn yellow, and the off-road vehicle tours them along the garnacha tracks. It is an à la carte outing with a single vehicle: book days ahead.

The kayak on the Siurana reservoir opens on autumn weekends, and in October the Trona ledge is done in cool air. On the long weekend, the 4x4 route is the first thing to sell out; the accommodation, the second.

September and October are the other good season for the Guara canyons, with summer's warm water. 12 October is a big festival in Aragon: book canyon, walkways and winery weeks ahead.

In October the Añisclo canyon has the beech woods changing colour and fewer cars than in summer; the narrow HU-631 is entered early. It is three hours from Tarragona: two nights, and Sunday's canyon, booked beforehand.

In October the Parrizal is toured without August's heat and with the mid-season ticket. At the Pilar many Aragonese arrive: buy the ticket with a time and avoid the last Sunday of the month, when El Salt closes.

Just after the harvest, the Codorníu cellars have the new grape fermenting and are toured underground by train. They open all year, holidays too: book the visit and lunch at the tower.

The good season for going up Sant Jeroni begins in October, with clean air and without summer's heat. The Aeri changes its timetable with the season: check it for your date and go up early.
Questions
After the harvest, in October and November, depending on the year.
Yes, it is their big festival. Book Alquézar, Aínsa or the Matarraña weeks ahead.
Geocaliahttps://www.geocalia.com/en/spain/catalonia/tarragona/getaways/pilar-long-weekend