, with a rainy season from October to April and a dry season from June to August, while May and September are transitional months.
The city is the capital of the state of Rondônia and is located in the northwest of Brazil, at 8 degrees south latitude, on the banks of the Madeira River, a tributary of the Amazon River. We are in the Amazon rainforest.
It is generally hot even in the austral winter, however, sometimes, especially in June and July, cool air masses from the south can lower the daytime temperatures to around or below 20 °C (68 °F), while night lows can drop to about 13 °C (55 °F).
Instead, from mid-August to October there can be very hot periods, in which the highest temperatures of the year are reached.
The best time to visit Porto Velho is from June to August, being the dry season.
. Here are the average temperatures.
January is generally a warm to hot, muggy month. The average temperature is of
27.3 °C, with a minimum of
23.4 °C and a maximum of
31.2 °C.

On the coldest nights of the month, the temperature usually drops to around
22 °C.

On the warmest days of the month, the temperature usually reaches around
34 °C.

Precipitation amounts to
320 mm, distributed over 19 days.
The day lasts on average 12 hours and 35 minutes.

There are on average 3.5 hours of sunshine per day. So, the sun shines 27% of the time.
The average humidity is 87%. Hence, the air is normally humid.
The average wind speed is of
5.1 kph.
February is generally a warm to hot, muggy month. The average temperature is of
27.2 °C, with a minimum of
23.5 °C and a maximum of
30.9 °C.

On the coldest nights of the month, the temperature usually drops to around
22 °C.

On the warmest days of the month, the temperature usually reaches around
33.5 °C.

Precipitation amounts to
315 mm, distributed over 19 days.
The day lasts on average 12 hours and 25 minutes.

There are on average 3.5 hours of sunshine per day. So, the sun shines 28% of the time.
The average humidity is 87%. Hence, the air is normally humid.
The average wind speed is of
5.1 kph.
March is generally a warm to hot, muggy month. The average temperature is of
27.5 °C, with a minimum of
23.6 °C and a maximum of
31.4 °C.

On the coldest nights of the month, the temperature usually drops to around
22 °C.

On the warmest days of the month, the temperature usually reaches around
34 °C.

Precipitation amounts to
275 mm, distributed over 20 days.
The day lasts on average 12 hours and 5 minutes.

There are on average 4 hours of sunshine per day. So, the sun shines 33% of the time.
The average humidity is 87%. Hence, the air is normally humid.
The average wind speed is of
4.8 kph.
April is generally a very hot, muggy month. The average temperature is of
27.7 °C, with a minimum of
23.6 °C and a maximum of
31.7 °C.

On the coldest nights of the month, the temperature usually drops to around
21.5 °C.

On the warmest days of the month, the temperature usually reaches around
34 °C.

Precipitation amounts to
250 mm, distributed over 17 days.
The day lasts on average 11 hours and 55 minutes.

There are on average 4.5 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 86%. Hence, the air is normally humid.
The average wind speed is of
4.6 kph.
May is generally a warm to hot, muggy month. The average temperature is of
27.3 °C, with a minimum of
23.1 °C and a maximum of
31.4 °C.

On the coldest nights of the month, the temperature usually drops to around
20 °C.

On the warmest days of the month, the temperature usually reaches around
34 °C.

Precipitation amounts to
125 mm, distributed over 11 days.
The day lasts on average 11 hours and 40 minutes.

There are on average 6 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is of
4.7 kph.
June is generally a warm to hot, muggy month. The average temperature is of
27.2 °C, with a minimum of
22.4 °C and a maximum of
32 °C.

On the coldest nights of the month, the temperature usually drops to around
19 °C.

On the warmest days of the month, the temperature usually reaches around
34 °C.

Precipitation amounts to
50 mm, distributed over 4 days.
The day lasts on average 11 hours and 35 minutes.

There are on average 7.5 hours of sunshine per day. So, the sun shines 65% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is of
4.5 kph.
July, the least warm month of the year, is generally a warm to hot, muggy month. The average temperature is of
27.2 °C, with a minimum of
21.3 °C and a maximum of
33 °C.

On the coldest nights of the month, the temperature usually drops to around
17 °C.

On the warmest days of the month, the temperature usually reaches around
35.5 °C.

Precipitation amounts to
25 mm, distributed over 3 days.
The day lasts on average 11 hours and 40 minutes.

There are on average 8.5 hours of sunshine per day. So, the sun shines 72% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is of
4.8 kph.
August is generally a very hot month. The average temperature is of
28.1 °C, with a minimum of
21.9 °C and a maximum of
34.3 °C.

On the coldest nights of the month, the temperature usually drops to around
17.5 °C.

On the warmest days of the month, the temperature usually reaches around
36.5 °C.

Precipitation amounts to
35 mm, distributed over 4 days.
The day lasts on average 11 hours and 50 minutes.

There are on average 7.5 hours of sunshine per day. So, the sun shines 64% of the time.
The average humidity is 69%.
The average wind speed is of
5 kph.
September, the hottest month of the year, is generally a very hot, muggy month. The average temperature is of
28.5 °C, with a minimum of
22.9 °C and a maximum of
34.1 °C.

On the coldest nights of the month, the temperature usually drops to around
19.5 °C.

On the warmest days of the month, the temperature usually reaches around
36.5 °C.

Precipitation amounts to
120 mm, distributed over 11 days.
The day lasts on average 12 hours and 5 minutes.

There are on average 6 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is of
5.3 kph.
October is generally a very hot, muggy month. The average temperature is of
28.3 °C, with a minimum of
23.3 °C and a maximum of
33.3 °C.

On the coldest nights of the month, the temperature usually drops to around
21.5 °C.

On the warmest days of the month, the temperature usually reaches around
36 °C.

Precipitation amounts to
195 mm, distributed over 13 days.
The day lasts on average 12 hours and 20 minutes.

There are on average 5.5 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is of
5.2 kph.
November is generally a very hot, muggy month. The average temperature is of
27.8 °C, with a minimum of
23.5 °C and a maximum of
32.2 °C.

On the coldest nights of the month, the temperature usually drops to around
21.5 °C.

On the warmest days of the month, the temperature usually reaches around
35 °C.

Precipitation amounts to
225 mm, distributed over 16 days.
The day lasts on average 12 hours and 30 minutes.

There are on average 4.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is of
5 kph.
December is generally a warm to hot, muggy month. The average temperature is of
27.4 °C, with a minimum of
23.4 °C and a maximum of
31.3 °C.

On the coldest nights of the month, the temperature usually drops to around
22 °C.

On the warmest days of the month, the temperature usually reaches around
34.5 °C.

Precipitation amounts to
320 mm, distributed over 19 days.
The day lasts on average 12 hours and 35 minutes.

There are on average 4 hours of sunshine per day. So, the sun shines 32% of the time.
The average humidity is 86%. Hence, the air is normally humid.
The average wind speed is of
4.8 kph.