Taxco's altitude keeps the climate comfortable year-round. Days are warm and sunny — typically 22–26°C — and nights drop to 10–15°C even in summer. The rainy season runs from June through September, bringing afternoon downpours that usually clear by evening. The cobblestones get slippery when wet. The dry months from October through May are the most comfortable for walking the town's steep streets.
The best reason to time a visit carefully is Semana Santa — Holy Week in the week before Easter. Taxco is one of the most dramatic venues in Mexico for the processions: hooded penitentes (some flagellating themselves, some dragging chains) wind through the cobblestone streets in nighttime ceremonies that are genuinely striking and unlike anything else in the country. The town fills up completely; book rooms months in advance and expect to pay a premium, but it is worth it if you are in Mexico during that period.
November brings Día de Muertos celebrations, with altars and offerings throughout the town and the market. The silver fair in December draws buyers from across the country and fills the streets with temporary stalls. Both are worth catching if you can arrange the timing. Outside these periods, weekdays are noticeably quieter than weekends — day-trippers from Mexico City arrive in numbers on Saturdays and Sundays, and the plaza and silver shops feel correspondingly crowded.