Uzbekistan has a strongly continental climate — hot summers and cold winters, with relatively little rain throughout the year. Spring and autumn are the sweet spots.
Spring (April–May) is the most beautiful time to visit. Temperatures are mild (15–25°C), the countryside is briefly green, the bazaars are full of early fruit, and the famous tilework of Samarkand and Bukhara glows in clear light. Navruz, the spring new year festival celebrated on 21 March, is one of the best times to experience Uzbek culture, with street celebrations, traditional food, and music across the country.
Autumn (September–October) rivals spring in comfort. The heat has broken, the melon and grape harvest is in full swing, and the markets are extraordinary. Skies are reliably blue and crowds thin out after the summer peak.
Summer (June–August) is hot everywhere and genuinely brutal in the desert cities. Bukhara can exceed 40°C and there's little shade in the historic centres. If you go in summer, start very early in the morning and retreat indoors during the middle of the day. The advantage is that you'll find better prices and fewer tour groups.
Winter (November–February) is cold — Tashkent can drop below freezing, and the desert regions get very cold at night. Snow occasionally falls on Samarkand. The major monuments are uncrowded and atmospheric in winter light, and accommodation prices drop significantly. It's a viable option if you dress for it and don't mind short days.
The Fergana Valley has a slightly wetter climate than the rest of the country and can be lush in spring. The Karakalpak Republic and the western desert see almost no rain any time of year.