Climate - Rio Branco (Brazil)

Rio Branco's climate is tropical, with a rainy season from October to April and a dry season in the austral winter, from June to August, while May and September are transitional months.
The city is the capital of the state of Acre and is located in the west of Brazil, 65 km (40 miles) away from the border with Bolivia, along the Acre River. We are in the Amazon rainforest.
The dry period, from June to August, is also the coolest at night (in fact, we are in the austral winter). From time to time, in addition, there may be cool periods due to the winds that blow from the Argentine Pampas, with highs of about 20 °C (68 °F) or even below, while at night the temperature can even reach 10 °C (50 °F).
However, from mid-August to October, the temperature rises and the hottest days of the year are recorded, before the rains.

The average temperature of the coldest month (June) is of 25.4 °C (77.8 °F), that of the warmest month (October) is of 27.8 °C (82.1 °F). Here are the average temperatures.
Precipitation amounts to 2000 millimeters (78.7 inches) per year: it is therefore abundant. It ranges from 30 mm (1.2 in) in the driest month (July) to 300 mm (11.8 in) in the wettest one (February). Here is the average precipitation.
The sea temperature ranges from 26 °C (26 °F) in August to 28.5 °C (28.5 °F) in March, April. Here are the average sea temperatures.
On average, there are around 1750 sunshine hours per year. Here are the average sunshine hours per day.

Rio Branco - Weather by month

Based on the period 1991-2020
(January - February - March - April - May - June - July - August - September - October - November - December)

In January, the average temperature is of 27.0 °C (81 °F), with a minimum of 22.7 °C (72.9 °F) and a maximum of 31.2 °C (88.2 °F).
On the coldest nights of the month, the temperature usually drops to around 21 °C (70 °F).
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F).
Precipitation amounts to 295 mm (11.6 in), distributed over 19 days.
On average, there are 110 hours of sunshine per month, i.e. 3.5 hours per day.
The average humidity is 87%.
The average wind speed is 5 kph (3 kph).

In February, the average temperature is of 26.9 °C (80 °F), with a minimum of 22.7 °C (72.8 °F) and a maximum of 31.1 °C (88 °F).
On the coldest nights of the month, the temperature usually drops to around 20.5 °C (69 °F).
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F).
Precipitation amounts to 300 mm (11.8 in), distributed over 17 days.
On average, there are 90 hours of sunshine per month, i.e. 3 hours per day.
The average humidity is 87%.
The average wind speed is 5 kph (3 kph).

In March, the average temperature is of 27.0 °C (81 °F), with a minimum of 22.7 °C (72.8 °F) and a maximum of 31.3 °C (88.3 °F).
On the coldest nights of the month, the temperature usually drops to around 20.5 °C (68.5 °F).
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F).
Precipitation amounts to 280 mm (11 in), distributed over 17 days.
On average, there are 115 hours of sunshine per month, i.e. 3.5 hours per day.
The average humidity is 87%.
The average wind speed is 5 kph (3 kph).

In April, the average temperature is of 26.9 °C (80 °F), with a minimum of 22.3 °C (72.1 °F) and a maximum of 31.4 °C (88.6 °F).
On the coldest nights of the month, the temperature usually drops to around 18.5 °C (65.5 °F).
On the warmest days of the month, the temperature usually reaches around 34.5 °C (94 °F).
Precipitation amounts to 205 mm (8.1 in), distributed over 13 days.
On average, there are 125 hours of sunshine per month, i.e. 4 hours per day.
The average humidity is 87%.
The average wind speed is 4 kph (3 kph).

In May, the average temperature is of 26.1 °C (79 °F), with a minimum of 21.2 °C (70.2 °F) and a maximum of 30.9 °C (87.6 °F).
On the coldest nights of the month, the temperature usually drops to around 16.5 °C (61.5 °F).
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F).
Precipitation amounts to 90 mm (3.5 in), distributed over 8 days.
On average, there are 155 hours of sunshine per month, i.e. 5 hours per day.
The average humidity is 84%.
The average wind speed is 4 kph (3 kph).

In June, the coldest month of the year, the average temperature is of 25.4 °C (78 °F), with a minimum of 20 °C (68 °F) and a maximum of 30.9 °C (87.6 °F).
On the coldest nights of the month, the temperature usually drops to around 15.5 °C (59.5 °F).
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F).
Precipitation amounts to 35 mm (1.4 in), distributed over 3 days.
On average, there are 175 hours of sunshine per month, i.e. 6 hours per day.
The average humidity is 82%.
The average wind speed is 4 kph (3 kph).

In July, the average temperature is of 25.5 °C (78 °F), with a minimum of 19 °C (66.3 °F) and a maximum of 32 °C (89.5 °F).
On the coldest nights of the month, the temperature usually drops to around 13.5 °C (56 °F).
On the warmest days of the month, the temperature usually reaches around 35 °C (95.5 °F).
Precipitation amounts to 30 mm (1.2 in), distributed over 3 days.
On average, there are 220 hours of sunshine per month, i.e. 7 hours per day.
The average humidity is 75%.
The average wind speed is 5 kph (3 kph).

In August, the average temperature is of 26.8 °C (80 °F), with a minimum of 19.8 °C (67.7 °F) and a maximum of 33.7 °C (92.6 °F).
On the coldest nights of the month, the temperature usually drops to around 14 °C (57.5 °F).
On the warmest days of the month, the temperature usually reaches around 37 °C (98 °F).
Precipitation amounts to 55 mm (2.2 in), distributed over 4 days.
On average, there are 180 hours of sunshine per month, i.e. 6 hours per day.
The average humidity is 68%.
The average wind speed is 5 kph (3 kph).

In September, the average temperature is of 27.8 °C (82 °F), with a minimum of 21.4 °C (70.5 °F) and a maximum of 34.2 °C (93.5 °F).
On the coldest nights of the month, the temperature usually drops to around 16.5 °C (61.5 °F).
On the warmest days of the month, the temperature usually reaches around 37 °C (98.5 °F).
Precipitation amounts to 85 mm (3.3 in), distributed over 6 days.
On average, there are 160 hours of sunshine per month, i.e. 5.5 hours per day.
The average humidity is 71%.
The average wind speed is 6 kph (4 kph).

In October, the warmest month of the year, the average temperature is of 27.8 °C (82 °F), with a minimum of 22.3 °C (72.1 °F) and a maximum of 33.4 °C (92.1 °F).
On the coldest nights of the month, the temperature usually drops to around 19 °C (66 °F).
On the warmest days of the month, the temperature usually reaches around 36.5 °C (97.5 °F).
Precipitation amounts to 155 mm (6.1 in), distributed over 10 days.
On average, there are 165 hours of sunshine per month, i.e. 5.5 hours per day.
The average humidity is 79%.
The average wind speed is 6 kph (3 kph).

In November, the average temperature is of 27.4 °C (81 °F), with a minimum of 22.5 °C (72.5 °F) and a maximum of 32.4 °C (90.3 °F).
On the coldest nights of the month, the temperature usually drops to around 19.5 °C (67 °F).
On the warmest days of the month, the temperature usually reaches around 35.5 °C (96 °F).
Precipitation amounts to 205 mm (8.1 in), distributed over 14 days.
On average, there are 140 hours of sunshine per month, i.e. 4.5 hours per day.
The average humidity is 83%.
The average wind speed is 6 kph (3 kph).

In December, the average temperature is of 27.0 °C (81 °F), with a minimum of 22.6 °C (72.7 °F) and a maximum of 31.4 °C (88.5 °F).
On the coldest nights of the month, the temperature usually drops to around 20.5 °C (69 °F).
On the warmest days of the month, the temperature usually reaches around 34 °C (93 °F).
Precipitation amounts to 265 mm (10.4 in), distributed over 18 days.
On average, there are 120 hours of sunshine per month, i.e. 4 hours per day.
The average humidity is 86%.
The average wind speed is 6 kph (3 kph).