León sits at 820 metres elevation on the meseta, which means cold winters and hot summers. Spring (April–June) and autumn (September–October) are the best times to visit — mild temperatures, fewer pilgrims on the Camino, and the city going about its normal life.
July and August are hot and tourist numbers peak as pilgrims push through. December through February is genuinely cold — below freezing at night is normal — but the city is quiet and atmospheric, and the cathedral looks extraordinary on a clear winter morning.
The Fiestas de San Juan y San Pedro in late June are León's main celebration: the week around 24 June brings concerts, processions, and a great deal of activity in the Barrio Húmedo.