The mild and dry winter of May through October is considered to be the best time to visit Bolivia. The middle of spring might reward you with lower prices and fewer crowds, but as you dive deeper into the dry season, the rates get significantly higher and places get busier. The sun shines brightly, making this period suitable for climbing Bolivian Highlands, sightseeing, and hiking. Don't miss a chance to party at the famous Fiesta de la Cruz or Fiesta del Gran Poder.
As the wet season starts in November, prepare for ubiquitous mud in Amazon areas. Salar de Uyuni looks fantastic, but there's nothing left to do on lowlands except dealing with summer heat, humidity, and mosquitoes.
In the highlands, rainfall is a rare occurrence, although some roads may get closed. But you'll definitely find a load of lavish landscapes in the Andes with quinoa and wildflowers in bloom.