Andorra has two clear seasons that drive most tourism, with a quieter shoulder period in between.
Winter (December–April): The main draw is skiing. Grandvalira, the largest ski area in the Pyrenees with over 200 km of pistes, and the smaller Vallnord (Pal-Arinsal) and Ordino-Arcalís resorts typically open in late November and run through Easter, sometimes into early May. December and January are quietest; February and March are peak season with higher prices and fuller slopes. The snow is generally reliable above 1,800 metres.
Summer (June–September): Hiking and mountain biking take over. Temperatures are warm but rarely oppressive — the capital sits at 1,023 metres, the passes at over 2,400 metres. The trails are uncrowded compared to the Pyrenees' more famous routes. Wildflowers are spectacular in June. The Meritxell national festival on September 8 marks the end of summer.
Spring and autumn: The shoulder months are quiet. Some mountain restaurants and ski-resort hotels close entirely. But the scenery is beautiful and the roads are empty. Good for a peaceful visit or a stop on a cross-Pyrenees drive.
Andorra la Vella averages around -1°C in January and 24°C in July. The mountains are much colder, and snow can fall at altitude any month of the year.