Ecuador has year-round good weather. Each of the four regions of Ecuador has a specific optimal tourist season.
The Andes region - mainly consists of highlands - has its winter season from June to September. Summer is experienced from December to March. Most tourists prefer to visit the Andes region during the winter season, as it is much cooler and drier than the summer, wherein it coincides with the rainy season.
The Pacific Coast region has its rainy share of the season during the months of December through May. Quite interestingly, the region experiences more sun in this season despite the occasional rain showers. This is the season considered to be the best time to visit the region.
The Oriente region is composed of tropical rainforests and lowlands and is best visited during the driest time of the year - from August to November. The dry season is suitable for jungle trekking adventures.
Lastly, the Galapagos region is located 500 miles away from the mainland. This region is quite friendly all year round - but animals tend to show up in specific seasons. For instance, nesting of sea tortoise and sea lions are best witnessed during the warm, rainy season.