Kazan has a continental climate — hot summers and very cold winters. The Volga and Kazanka freeze for several months a year.
Summer (June–August) is the easiest visit: temperatures around 22–28°C, long daylight, all the outdoor cafes, river cruises operating, and the city at its most photogenic. Sabantuy, the Tatar harvest festival, is held in late June and is a major cultural event with horse races, wrestling, traditional food, and music. Autumn (September–October) is cooler and quieter, and the trees in the parks turn well; a good time for sightseeing if you don't mind cooler weather.
Winter (December–February) is genuinely cold, with temperatures regularly dropping below -20°C. The Kremlin under snow is striking, the Kazanka embankment becomes a skating rink, and the New Year's market on Bauman Street is one of the best in central Russia. Spring is the worst time: mud and meltwater for several weeks before the city dries out in late April.