When to visit Ecuador
Introduction
Ecuador is situated on the equator and hence, there are only two seasons: winter (rainy season) and summer (dry season).
Due to the varied geographical structure of the country it is best to divide the climate information in accordance to these areas:
The Galápagos Islands: The weather in the Galápagos Islands is largely determined by ocean currents. June to December is cool and dry and in December, there's a definable climate pattern of hot sunny mornings followed by clouds and sparse showers in the afternoons. January to May is generally hot, humid and wet.
The Andes: There is a varied range in temperature and weather, which depends on the altitude and the time of year - as a general rule, the higher the altitude, the colder it is likely to be. The rainy season in the Andes takes place from December to May and the rest of the year is relatively sunny.
The Amazon: 
The climate in the Amazon is fairly consistent throughout the year - very humid and warm. Average temperatures hover around the mid 20s and the dry season (relatively speaking, for a rainforest) runs between from November to March. Short term Amazonian weather is difficult to predict.
The coast:
 During the dry season, you can nearly always expect hot, sunny days with temperatures ranging between in the mid-to high 20s. The rainy season runs from December to May.