Menton has the warmest winter climate of any town in France, sheltered by the Alps to the north and open to the Mediterranean to the south. Average January temperatures hover around 10°C — mild enough for walking and garden visits without the summer crowds.
February brings the Fête du Citron (Lemon Festival), which is the best reason to visit out of season. The festival runs for around three weeks and the town fills with visitors, but accommodation remains far cheaper than in summer.
April and May are ideal: the gardens are at their most spectacular, the weather is warm enough to swim, and the tourist density is manageable. Summer (July–August) is hot, expensive, and crowded — the Riviera effect. September is a good compromise: the sea is warm from the summer, the crowds thin out, and the light is beautiful.