Spring and summer
April is unpredictable — 12-16°C, rainy, but daffodils across the Pétrusse valley. May and June are ideal: 18-22°C, long evenings, and the Schueberfouer fair hasn’t started so hotels are still reasonable. July and August hit 24-28°C and get busy — the Schueberfouer funfair (end August to early September) is genuinely worth timing a trip around. Book hotels 6-8 weeks ahead in these months.
Autumn and winter
September is my personal pick: 18-22°C, wine harvest along the Moselle, fewer tourists. October brings serious autumn colour in the valleys and Mullerthal. November-February is grey, damp and 2-8°C — but the Christmas markets on Place d’Armes and Place de la Constitution (late Nov to Dec 24) are genuinely lovely and hotel prices drop 30%. January and February are the cheapest and quietest months.
Good to know
Does it snow?+
Occasionally — a few days most winters, but real snow that sticks is rare in the city. The Ardennes north of Vianden gets more, and Baraque de Fraiture across the Belgian border has a small ski area.
When are hotels cheapest?+
January, February, and the two weeks after New Year. Also mid-July and August weekends when business travellers vanish — the reverse of most European capitals.