Guanajuato in March

October through April gives you the best weather — warm days around 75°F, cool nights that might dip to 50°F. Pack layers because the altitude makes temperature swings dramatic. December and January are peak season, meaning crowds and higher prices, but also the most events and energy. Festival Internacional Cervantino in October transforms the city into a massive arts festival. Hotels book up months in advance and prices triple, but if you score accommodations, you'll see world-class performances in venues from grand theaters to tiny plazas. Worth it if you plan ahead. May through September brings rain, usually afternoon thunderstorms that turn the cobblestones slippery and flood the lower tunnels. The city looks gorgeous in the rain, but navigation becomes trickier. Fewer crowds mean better deals — expect 30% discounts on hotels. Avoid Easter week unless you enjoy sardine-can crowds. Mexican families descend on Guanajuato en masse, and the narrow streets become nearly impassable. Same goes for Day of the Dead — beautiful traditions, impossible logistics.