Spring (April–June) is the best time to visit. Temperatures are pleasant across the country — warm in the lowlands, still cool in the mountains — and the countryside is green. The traditional Novruz (Persian New Year) celebrations in late March and early April are worth timing around if you can: bonfires, feasts, and a palpable sense of collective joy.
Autumn (September–October) is a close second. The heat breaks, the light turns golden, and harvest markets fill town squares. Wine is produced in the Ganca region and the Shamkir district; autumn is when you can taste it fresh.
Summer (July–August) is hot in Baku — regularly above 35°C — and the Apsheron peninsula bakes. Bakuvians flee to the mountains or the north. Paradoxically, this is a good time for the highlands: the Caucasus foothills around Sheki, Qusar, and Gabala are at their greenest. Mud volcano tourism around Gobustan works year-round, but summer heat makes the midday visit miserable.
Winter (November–March) is cold and grey in Baku and the lowlands. The upside: the ski resorts at Shahdag and Tufandag (near Ganca) open from December. Shahdag, in the mountains near Qusar, is a proper ski resort with modern lifts and challenging runs. Accommodation in Baku is cheaper in winter and the city is less crowded.