Question

why there is not much different in range of temperature in Manaus

Answer 1

The meteoblue climate diagrams are based on 30 years of hourly weather model simulations and available for every place on Earth. They give good indications of typical climate patterns and expected conditions (temperature, precipitation, sunshine and wind). The simulated weather data have a spatial resolution of approximately 30 km and may not reproduce all local weather effects, such as thunderstorms, local winds, or tornadoes.

Answer 2

Manaus is positioned in the core/focal of the Brazilian Amazon and all seasons in this region are very humid and hot and are difficult to differentiate temperature-wise, due to its nearness to the equator.  

EXPLANATION:

All the seasons in the Manaus region are very humid and hot and humid and are difficult to differentiate temperature-wise due to its closeness to the equator.

Owing to its latitude, Manaus enjoys an equatorial climate, where temperatures differ very little during the day as well as year. The summer is usually a little cooler because of greater precipitation amount, which is distributed all through the year, being of convective origin bringing great amounts of precipitation in a short time.

Dry seasons are from June-October, while wet seasons are from December all through May. All the other months are generally humid and hot. Also Manaus being located nearby to the Amazon River Basin, it experiences, primarily, an equatorial climate or a wet tropical climate, also described as a tropical monsoon climate.