Vitoria sits on a plateau at 525 metres above sea level — higher and colder than the coastal Basque cities. Winters are sharp and grey, with frequent fog rolling off the surrounding hills; summers are warm but rarely sweltering, with cool evenings.
The best months are May, June, and September: long days, comfortable temperatures, and the city in full pavement-café mode. The patron saint festival around 4 August (the Fiestas de la Virgen Blanca) is the loudest week of the year and the city's defining event — five days of music, processions, and bullfights opened by the Bajada del Celedón. The Jazz Festival in mid-July is the other obvious time to plan a visit around.