Rio Branco climate — normals and trends
Rio Branco (Brazil) has a tropical savanna climate (Aw) under the Köppen-Geiger classification. Its mean annual temperature is 25.3 °C and it receives 1,691 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is September (26.5 °C on average) and the coldest is June (24.1 °C). Rainfall peaks in February.
Rio Branco averages 0 frost days, 218 hot days (≥ 30 °C) and 219 rainy days per year.
Rio Branco has warmed by +1.2 °C between 1940 and 2025, or +0.14 °C per decade. This trend is statistically significant.
The hottest day of the period reached 40.2 °C (on 30 September 2010) and the coldest 8.4 °C (on 19 July 1975).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
Rio BrancoAcre
- coords
- -9.97°, -67.81°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
25.3°C
Average daily high
30.6°C
Average daily low
21.7°C
Annual rainfall
1,691mm
Sunshine / day
9.3h
Mean relative humidity
84%
Average peak wind
9.1km/h
Seasonal range
2.4°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
218 d/yr
Rainy days (≥ 1 mm)
219 d/yr
Annual snowfall
0.0 cm
Average feels-like high
36.1 °C
Average feels-like low
25.3 °C
Average peak gust
26.4 km/h
Tropical nights (≥ 20 °C)
315 d/yr
Solar radiation
17.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.2 °C
since 1940
+0.1 °C per decade · r² = 0.45 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
40.2 °C
30 September 2010
Coldest day
8.4 °C
19 July 1975
Wettest day
146 mm
16 May 2022
Windiest day
27.9 km/h
25 June 1994
Strongest gust
61.2 km/h
13 August 1978
Hottest feels-like
44.4 °C
6 October 2024
Coldest feels-like
5.3 °C
19 July 1975
Sunniest day
12.6 h
17 December 1941
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 30.7 °C | +0.9 °C | 221 mm | -21 mm |
| Feb | 29.8 °C | +0.2 °C | 305 mm | +61 mm |
| Mar | 30.4 °C | +0.6 °C | 267 mm | +29 mm |
| Apr | 30.3 °C | +0.7 °C | 216 mm | +53 mm |
| May | 30.8 °C | +1.7 °C | 93 mm | +9 mm |
| Jun | 29.7 °C | +0.2 °C | 41 mm | +6 mm |
| Jul | 31.7 °C | +0.8 °C | 31 mm | +9 mm |
| Aug | 33.3 °C | +0.7 °C | 18 mm | -20 mm |
| Sep | 32.8 °C | -0.1 °C | 93 mm | +19 mm |
| Oct | 32.4 °C | +0.4 °C | 139 mm | +6 mm |
| Nov | 30.9 °C | +0.1 °C | 209 mm | +22 mm |
| Dec | 29.6 °C | -0.4 °C | 308 mm | +77 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Rio Branco?
Rio Branco has a tropical savanna climate (Köppen Aw). Over 1940-2025, the average annual temperature is 25.3 °C and it receives 1,691 mm of precipitation per year.
What is the hottest day ever recorded in Rio Branco?
The hottest day measured in Rio Branco between 1940 and 2025 was 30 September 2010, reaching 40.2 °C.
What is the coldest day in Rio Branco?
The coldest day measured in Rio Branco between 1940 and 2025 was 19 July 1975, at 8.4 °C.
Does it snow in Rio Branco?
Almost never: Rio Branco sees virtually no snow, with about 0 frost days per year.
Has the climate of Rio Branco warmed?
Yes: Rio Branco warmed by +1.2 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Rio Branco?
The wettest day measured in Rio Branco between 1940 and 2025 was 16 May 2022, with 146 mm of rain in 24 hours.
What was the windiest day in Rio Branco?
The windiest day measured in Rio Branco between 1940 and 2025 was 25 June 1994, with winds reaching 27.9 km/h.
What is the warmest month in Rio Branco?
The warmest month in Rio Branco is September (26.5 °C on average); the coldest is June (24.1 °C).
How much does it rain in Rio Branco?
Rio Branco receives on average 1,691 mm of precipitation per year, spread over about 219 rainy days.
Is it sunny in Rio Branco?
Rio Branco gets on average 9.3 hours of sunshine per day, roughly 3,395 hours per year over 1940-2025.
Are there tropical nights in Rio Branco?
Yes: Rio Branco has on average 315 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Rio Branco?
In Rio Branco, between 1940 and 2025, the highest apparent temperature reached 44.4 °C on 6 October 2024, and the lowest was 5.3 °C on 19 July 1975.
Compare Rio Branco with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Rio Branco