Ouro Preto sits at 1,200 metres above sea level — cooler than the Brazilian coast and noticeably cold at night between May and August, when the dry winter brings clear days of 22°C and nights that drop near freezing. Bring a fleece even in mid-winter. The summer rainy season runs from December to March: warm afternoons, frequent thunderstorms, fewer tourists.
The town's most famous event is Holy Week. Processions cover the streets with carpets of coloured sawdust depicting religious scenes — the whole town turns out, and rooms book up months in advance. The other big draw is the July Festival de Inverno, when the federal university hosts a fortnight of music, theatre, and dance across the colonial buildings.
September and October — the start of the rains but still mostly dry — are arguably the most pleasant months: warm, green, and uncrowded.