Rio Branco climate
Rio Branco (Acre, Brazil) has a tropical savanna (dry winter) climate (Köppen Aw). The average temperature over the year is 26 °C78 °F, and about 1,737 mm68 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Rio Branco climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 2883 | 2373 | 2578 | 25710 |
| Feb | 2882 | 2373 | 2578 | 25510 |
| Mar | 2882 | 2373 | 2577 | 2429.5 |
| Apr | 2882 | 2272 | 2577 | 1606.3 |
| May | 2882 | 2170 | 2476 | 793.1 |
| Jun | 2882 | 2069 | 2476 | 331.3 |
| Jul | 2985 | 2068 | 2576 | 251.0 |
| Aug | 3290 | 2169 | 2680 | 431.7 |
| Sep | 3492 | 2272 | 2882 | 763.0 |
| Oct | 3391 | 2373 | 2882 | 1315.2 |
| Nov | 3187 | 2373 | 2780 | 1977.8 |
| Dec | 2883 | 2373 | 2678 | 2399.4 |
| Year | 3492 | 2068 | 2678 | 1,73768 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 92% | 88% | 4.7 | 12:39 |
| Feb | 93% | 89% | 4.5 | 12:26 |
| Mar | 93% | 86% | 4.6 | 12:11 |
| Apr | 92% | 76% | 4.6 | 11:53 |
| May | 91% | 66% | 4.4 | 11:40 |
| Jun | 88% | 53% | 4.4 | 11:33 |
| Jul | 81% | 46% | 4.9 | 11:35 |
| Aug | 70% | 52% | 5.0 | 11:47 |
| Sep | 69% | 65% | 5.0 | 12:04 |
| Oct | 74% | 80% | 5.1 | 12:20 |
| Nov | 83% | 83% | 5.0 | 12:35 |
| Dec | 91% | 87% | 4.6 | 12:42 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Rio Branco is like
The warmest month is September, with an average high of 34 °C92 °F and a low of 22 °C72 °F. The coldest is June, when highs average 28 °C82 °F and lows 20 °C69 °F. Seasonal differences are small — just 3.7 °C6.7 °F between the warmest and the coolest month.
It is wet, with about 1,737 mm68 in of precipitation per year. The wettest three-month stretch is January–March, which brings 43% of the annual total. The wettest month is January (257 mm10 in), the driest is July (25 mm1.0 in).
Relative humidity ranges from 69% in September to 93% in March. The clearest skies (lowest average cloud amount, 46%) are typical of July. Average wind speed near the ground ranges from 0 km/h (0 mph) in October to 1 km/h (0 mph) in June. Daylight lasts from about 11.5 hours in June to 12.7 hours in December.
Best time to visit Rio Branco
Based on these averages, the most comfortable months for sightseeing and outdoor activities are June and July. Average highs then reach 28 °C82 °F to 29 °C85 °F. Precipitation is 25 mm1.0 in to 33 mm1.3 in per month.
The most challenging month is January, which is very wet (257 mm10 in) and humid (92% relative humidity).
Comfort score: months are ranked by how close they come to an ideal. That means an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Rio Branco
- Wetter months (November–April) — highs 2882 to 31 °C87 °F, lows 2272 to 23 °C73 °F, about 225 mm8.9 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and a good rain jacket or umbrella and quick-drying shoes.
- Drier months (May–October) — highs 2882 to 34 °C92 °F, lows 2068 to 23 °C73 °F, about 64 mm2.5 in of precipitation a month. Pack very light, breathable clothing, a sun hat and plenty of water.
How Rio Branco compares
World Climates covers 223 places in Brazil. By annual mean temperature, Rio Branco is the 61st warmest of them. By annual precipitation, it is the 21st wettest. See all of them on the Brazil climate page.
Some places in other countries have a very similar pattern of temperature and rainfall (with seasons shifted for the other hemisphere). The closest matches are Man (Ivory Coast, Aw), Ijebu Ode (Nigeria, Aw) and Warri (Nigeria, Aw).
Nearby places
- Climate in Porto Velho 449 km · 27 °C80 °F · 1,711 mm67 in
- Climate in Cusco 601 km · 11 °C52 °F · 718 mm28 in
- Climate in Ji Paraná 649 km · 27 °C80 °F · 1,554 mm61 in
- Climate in Juliaca 664 km · 10 °C49 °F · 482 mm19 in
- Climate in Leticia 683 km · 26 °C79 °F · 2,558 mm101 in
- Climate in Puno 695 km · 10 °C50 °F · 421 mm17 in
- Climate in La Paz 727 km · 8 °C47 °F · 647 mm25 in
- Climate in Pucallpa 761 km · 27 °C81 °F · 1,382 mm54 in
Frequently asked questions
What is the warmest month in Rio Branco?
September is the warmest month in Rio Branco. Its average high is 34 °C (92 °F) and its average low is 22 °C (72 °F).
What is the coldest month in Rio Branco?
June is the coldest month. Its average high is 28 °C (82 °F) and its average low is 20 °C (69 °F).
When does it rain the most in Rio Branco?
January is the wettest month with about 257 mm (10.1 in) of precipitation. July is the driest with about 25 mm (1.0 in).
What is the best time to visit Rio Branco?
Judging by long-term averages, the most comfortable months are June and July.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station. So they can differ from airport records. The gaps are largest on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.