December’s crisp air (4°C/39°F to 14°C/57°F) and short days (sunrise 8:25 AM, sunset 6:05 PM) set the stage for festive lights, Christmas markets, and Nochevieja celebrations in Plaza de las Tendillas. The city is calm except during the Puente de Diciembre holiday, when hotels fill quickly. Churros and hot chocolate are winter staples, and monuments are crowd-free. Occasional rain and cool evenings call for warm layers.