October to March is the best time to visit. Temperatures are comfortable (15–25°C by day), the air is clearer, and the ghats are at their most photogenic. The Dev Deepawali festival in November (on the full moon after Diwali) is spectacular — every ghat is lit with earthen lamps and the entire riverbank glows.
April to June brings intense heat (40°C+), but pilgrim numbers remain high and the city never quiets. The Ganga Dussehra festival in May–June is worth timing a visit around.
July to September is monsoon season. The river rises dramatically and can flood the lower ghats entirely. Travel in the lanes becomes difficult. However, the humidity breaks the heat, and the atmosphere of a monsoon Varanasi is unlike anywhere else — the city turns inward, the ghats go quiet, and the smell of incense and river water intensifies.
Avoid: Holi weekend brings enormous crowds and some safety concerns for solo women travellers.