during the winter months, one of the things to
look forward to is a phenomenon called 'maré
roxa', or 'purple tide'.
the purple tide happens after a cold front leaves rio de janeiro,
and marine currents coming from the south of brazil get to rio's
coastline, paired with winds from the south-west.
the result is a spectacularly clear, calm, warm crystalline water
along the oceanic beaches, with temperatures between 0 and 25 degrees
celsius (68 and 77 degrees
fahrenheit).