Map from Google - Ecuador

As the name suggests, Ecuador is bisected (in the north) by the Equator, the imaginary line that divides the Earth, and in which the days last 12 hours throughout the year. One would expect, therefore, an equatorial climate, hot and humid with year-round rains, but this is only true for the eastern part of the country and the northernmost part of the coast, both covered by forests. The central part is in fact crossed by the Andes and is therefore more or less cold depending on altitude, while almost the entire western plain and coast, is affected by a cool ocean current, which lowers a bit the temperature and makes the climate more arid.

Ecuador, equatorial climate
In the far north-west of Ecuador, on the border with Colombia, and across the vast Amazon area to the east, the climate is equatorial, ie hot and humid all year round. The amount of rainfall is quite remarkable, around 2,800/3,000 millimetres (110/118 inches) per year in most of the plains. The rains occur primarily in the form of heavy showers or thunderstorms in the afternoon. The (relatively) less rainy period goes from August to November in the north-west, while in the Amazon it goes from November to March, when, however, from 150 to 200 mm (6 to 8 in) of rain per month fall. The average temperature ranges from 26 °C (79 °F) in the Southern Hemisphere's summer (December-January), to 23 °C (73 °F) in winter (with July as the coolest month). Relative humidity is constantly high and makes the heat sweltering.
In the central area of the country, along the eastern slopes of the Andes, we find the rainiest part of the country. In the city of Puyo, at almost 1,000 metres (3,300 feet) above sea level, therefore at the boundary between the tierras calientes and the tierras templadas, 4,300 millimetres (170 inches) of rain per year fall. It rains almost every day, and sunshine is scarce, because the sky is often cloudy.
Here is the average precipitation.
Average precipitation - Puyo
Prec. (mm)3002953904553253903403453553603653704290

The only consolation is that the altitude makes the temperatures pleasant, around 20 °C (68 °F) as daily average all year round. Here it doesn't really make sense to speak of "best time", however, January and February are the only months in which rainfall amounts to "only" 300 mm (12 in) per month.
Here are the average temperatures of Puyo.
Average temperatures - Puyo
Min (°C)171717171716161616161717
Max (°C)262626262625252627272727
Min (°F)636363636361616161616363
Max (°F)797979797977777981818181

Ecuador, climate of the west
West of the Andes we find a plain, which has a tropical climate, with a dry season (which goes from July to November in the north, and from May to December in the south), and a wet season (December to June in the north, January to April in the south), although the rainfall varies greatly: in general, the coasts are drier than the areas at the foothills of the Andes, and the north receives more rainfall than the south.
The temperature is high throughout the year, however, it decreases slightly in the austral winter and in spring, as we can see from the temperature of Manta, located in the central part of the coast.
Average temperatures - Manta
Min (°C)222322222221202020202021
Max (°C)303030303029282828282829
Min (°F)727372727270686868686870
Max (°F)868686868684828282828284

On much of the coastline, the cool sea current inhibits the formation of clouds able to generate rains, for many months a year. However, the sunshine amount is low, because even in the dry period, the sky is often cloudy, and fogs and mists often form. Here is the average rainfall.
Average precipitation - Manta
Prec. (mm)4095702535511135254

Along the southern part of the coast (see Santa Elena, General Villamil Playas), there's even a desert, where rainfall is lower than 100 mm (4 in) per year, and is concentrated in the period from January to April. which, however, is when tourists frequent the beaches, also because the sea is warmer. Even though generally the rains are very scarce also in this period, in the years of El Niño there can be heavy rains, and even floods. In addition, in this period, although it's the warmest of year, sunshine is not so frequent, because there is often a haze that covers the sun. In the period from June to October the heat is less intense and therefore more enjoyable, and it never rains. It must be said that the amount of sunshine is not good even in this period.
Continuing north, as mentioned in Manta the rainfall amounts to about 250 mm (10 in) per year, while in Bahia de Caraquez and in Esmeraldas it's about 500 mm (20 in).
As you move away from the coast, the rains increase, reaching the highest levels at the foot of the Andes. From south to north, precipitation ranges from 1,000 mm (40 in) per year in Guayaquil, to 2,000 mm (79 in) in Montoya, to 2,800 mm (110 in) in Santo Domingo de los Colorados, where it rains a lot from February to April, and it still rains a lot in June: here the driest months are definitely July and August, with less than 40 mm (1.6 in) per month, anyway, from July to November, rainfall drops below 70 mm (2.8 in) per month.
Here is the average rainfall of Guayaquil, in the south central part, a short distance from the coast.
Average precipitation - Guayaquil
Prec. (mm)2302402501506035101236351026

In the north-central part of the coast, the sea is warm all year round, while in the southern part it becomes a little cool from July to November, as you can see in the following table.
Sea temperature - Guayaquil
Sea (°C)242625242423222121222223
Sea (°F)757977757573727070727273

As already mentioned, the climate of Ecuador is affected by a cycle in which normal periods alternate with those of El Niño and La Niña. During the years of "El Niño", the sea level rises by about 2/3 centimetres (1 inch), the water (and air) temperature rises by a few degrees, and heavy rains affect the coastal zones, which are normally arid, in the period from December to May. The Andean areas receive more rainfall than usual as well. On the contrary, during the years of "La Niña", the temperature of the sea (and of the air) becomes cooler than normal, and rainfall more scarce.

Ecuador, climate of the Andes
The central part of Ecuador is crossed by the Andes, which are divided into two mountain ranges, and include several volcanoes of considerable height. Glaciers start at a height of about 5,000 metres (16,500 ft). In the Cordillera Occidental lies the volcano Chimborazo, the highest peak of the country with its 6,268 metres (20,564 feet), while in the Cordillera Real we find Cotopaxi, 5,897 metres (19,347 ft), Antisana, 5,704 metres (18,714 ft) and Cayambe, 5,790 metres (18,996 ft).


Between the mountain ranges there are plateaus, in which we find important cities, like the capital Quito, which is the second highest capital in the world, being located at 2,850 metres (9,350 ft) above sea level. Here the temperatures are mild, spring-like throughout the year: highs are around 18/20 °C (64/68 °F), although some days can be a bit warmer, and lows are around 10 °C (50 °F), although sometimes at night the temperature can approach the freezing point.
Average temperatures - Quito
Min (°C)101010101099999910
Max (°C)181818181819191920191918
Min (°F)505050505048484848484850
Max (°F)646464646466666668666664

The rainfall amounts to 1,200 mm (47 in) per year, and is frequent and abundant from October to May. Therefore, the best time here goes from June to mid-September, but in reality the only months where it rarely rains are July and August. In the capital, the amount of sunshine throughout the year is acceptable, but not more than that, because the sky is quite often cloudy. Here is the average precipitation.
Average precipitation - Quito
Prec. (mm)12013015518513055202580135951051235

At higher altitudes, the temperature decreases further. At 3,500 metres (11,500 ft), the daily average temperature is around 7/8 °C (45/46 °F) throughout the year, this means that it's cold, and at night it can freeze.
There are other cities that are located at high altitudes in the Andes, but are drier than the capital. For example in Cuenca, in the south, rainfall totals 710 mm (28 in) per year, while it drops to 625 mm (24.5 in) in Ibarra, located in the north.
Along the western slopes of the Andes, even at low altitudes, the sky is often overcast during the drier season (July-December).

Wanting to find a single period which is best to visit Ecuador, we can choose the Southern Hemisphere's winter, and in particular the months of July and August, which are the least rainy, and in some areas also the sunniest. It must be said, however, that in the areas of the forest it rains a lot even in this period, and the amount of sunshine is low. On the other hand, along the west coast, although it rarely rains, the sky is often cloudy.

What to pack

For the Amazon, in the plain, loose fitting, lightweight clothing of natural fibres, maybe with long sleeves for mosquitoes; possibly a light sweatshirt and a light raincoat for thunderstorms. For the Amazon at low-mountain altitudes (see Puyo), light clothes, sweatshirt and light jacket for the evening, raincoat.
For the western plains and the coast: light clothing, raincoat and lightweight sweatshirt in the rainy season (December to June in the north, January to April in the south), sweatshirt for the evening in the cooler season (June to September).
For the southernmost part of the coast, throughout the year, a sweatshirt for the evening; from June to September, a sweater or sweatshirt, a light jacket.
For Quito and the Andes, clothes for spring and autumn, sweatshirt or sweater, warm jacket for the evening, sun hat; raincoat or umbrella especially from October to May.
For the highest mountains, warm clothes, down jacket, hat, gloves, scarf.

See also the climate of the Galápagos.