Many visitors from outside Brazil are not prepared to feel cold in this tropical country. This is precisely the case in Curitiba, located off from the tropic parallel, and elevated by an altitude of almost 1000 meters above the sea level. These factors mean that winters (jun-sep) can reach freezing temperatures specially by night, which make coats and further protections necessary. Even in the other seasons, cold nights are not something unexpected, albeit it will rarely go down to freezing levels. Summers (dec-mar) tend to be mild, with some hotter days of maximum through 30's C or 90's F, but occasional nights of 10's C or 50's F.
Curitiba is very well served of rain, there's no dry season, and the dwellers are not familiar with a time lapse of more than 4 ou 5 days without showers. There are some meteorological issues that makes long periods of a permanent light rain or drizzle, which may comprises several weeks, typically foggy and grey, barely similar as London.
Snow is very rare and the last precipitations took part in 1975. But there's lots of sites in 3h or 4h of traveltime that snows every year, specially Palmas (300km) and Sao Joaquim (400km). Frost, nevertheless, is very common within the city limits and produces painting-like landscapes in the urban parks, notably Barigui Park and Jardim Botanico (until 8 a.m., before the sunlight starts to melt the frost)
