Late April is the perfect time to visit Uyuni, as you can expect to see both the dry salt desert and the giant mirror effect. It is not as cold as in winter and rainfall is limited. The smaller number of tourists also means that you can get better deals for hotels and tours.
Otherwise, there is no good or bad time to visit the salt flats, it is simply a question of what you are looking for.
Salar de Uyuni
Here are some tips to help you decide when to visit the Salar de Uyuni:
At the beginning of every year, the Uyuni Salt Flat in Bolivia becomes the largest natural mirror in the world.
Water covers the Salar
As this giant desert of salt is covered by water during the rainy season, it reflects light creating almost impossible optical illusions.
Reflections of the sky
The Salt Flat is a huge white beach-like desert during the winter dry season.
The salt flat during winter
If you want the best climate, visit between September and November.
In summer, between January and March. Generous rains fall on the bolivian highlands, turning the Uyuni Salt Flats into something similar to a giant lake a few centimeters deep.
It tends to rain the most in February, but this can be quite unpredictable. Also, be aware that too much rain will melt the salt and make large parts of the salt flat inaccessible for tours.
Water accumulates on the salt
Several rivers deposit their sediments in the Uyuni Salt Flats and the water accumulates on the nearly waterproof salty surface.
Another less-known attraction is the large number (around 25000) of flamingos that gather in the Eduardo Avaroa Reserve during the rainy season for mating.
This activity is also highly popular with tourists when visiting Uyuni.
In short, any time is good to visit the Salar de Uyuni. Each season offers a unique perspective and features.
Photo by Gabor Kosaras