Climate and average weather in Rio Branco
In Rio Branco, the weather is muggy, sweltering, wet, and partly cloudy and remarkably steady, with daytime highs holding near sweltering levels all year. The wettest stretch peaks around January.
Over the course of the year, the temperature in Rio Branco typically varies from 20°C to 33°C, and is rarely below 15°C or above 37°C. September is the hottest month of the year, while May is the coldest.
Based on the travel score, the best time of year to visit Rio Branco for warm-weather activities is from mid May to early August.
- Hottest
- Sep
- 33°
- Coldest
- May
- 21°
- Wettest
- Jan
- 255 mm
- Driest
- Jul
- 21 mm
- Rain / yr
- 1726 mm
- 216 wet days
- Daylight
- 11.4–12.6 h
- shortest–longest
- Elevation
- 153 m
- 10.0°S
- Clearest
- Jul
- 39% cloud
Rio Branco is human settlement in Acre, Brazil.
- Founded
- 1882
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Rio Branco weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid May to early August.
Temperature through the year
Daily average highs and lows in Rio Branco, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
Temperatures in Rio Branco stay fairly even through the year, without a distinct hot or cool season. The warmest month is September, with an average high of 33°C and low of 22°C; the coolest is May, with an average low of 21°C and high of 30°C.
Days typically run about 9°C warmer than nights, with the widest day–night swing (around 13°C) in August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 30 | 30 | 30 | 30 | 30 | 30 | 31 | 33 | 33 | 33 | 31 | 30 |
| Avg low (°C) | 23 | 23 | 23 | 22 | 21 | 20 | 20 | 20 | 22 | 23 | 23 | 23 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 30 | 23 |
| Feb | 30 | 23 |
| Mar | 30 | 23 |
| Apr | 30 | 22 |
| May | 30 | 21 |
| Jun | 30 | 20 |
| Jul | 31 | 20 |
| Aug | 33 | 20 |
| Sep | 33 | 22 |
| Oct | 33 | 23 |
| Nov | 31 | 23 |
| Dec | 30 | 23 |
How hot and cold Rio Branco really feels
The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.
On the hottest afternoons, once humidity is folded in, Rio Branco feels like about 37°C (around October 13). Nearly every day a year carries some heat stress, peaking in October.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 35 | 35 | 35 | 35 | 33 | 33 | 33 | 35 | 37 | 37 | 36 | 35 |
| Air high (°C) | 30 | 30 | 30 | 30 | 30 | 30 | 31 | 33 | 33 | 33 | 31 | 30 |
| Feels-like low (°C) | 23 | 23 | 23 | 22 | 21 | 20 | 19 | 20 | 22 | 23 | 23 | 23 |
| Air low (°C) | 23 | 23 | 23 | 22 | 21 | 20 | 20 | 20 | 22 | 23 | 23 | 23 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 35 | 30 | 23 | 23 |
| Feb | 35 | 30 | 23 | 23 |
| Mar | 35 | 30 | 23 | 23 |
| Apr | 35 | 30 | 22 | 22 |
| May | 33 | 30 | 21 | 21 |
| Jun | 33 | 30 | 20 | 20 |
| Jul | 33 | 31 | 19 | 20 |
| Aug | 35 | 33 | 20 | 20 |
| Sep | 37 | 33 | 22 | 22 |
| Oct | 37 | 33 | 23 | 23 |
| Nov | 36 | 31 | 23 | 23 |
| Dec | 35 | 30 | 23 | 23 |
Average hourly temperature in Rio Branco
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on September afternoons, near 33°C, and coldest before dawn in May, near 21°C.
Rio Branco weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 30° / 23° | 255 | 27.7 | 12.5 | 2.8 |
| Feb | 30° / 23° | 240 | 25 | 12.3 | 2.8 |
| Mar | 30° / 23° | 249 | 27.2 | 12.1 | 2.8 |
| Apr | 30° / 22° | 160 | 22.8 | 11.8 | 3.2 |
| May | 30° / 21° | 76 | 15.4 | 11.5 | 4.3 |
| Jun | 30° / 20° | 30 | 6.8 | 11.4 | 5.3 |
| Jul | 31° / 20° | 21 | 4.2 | 11.5 | 5.1 |
| Aug | 33° / 20° | 38 | 6.3 | 11.7 | 4.0 |
| Sep | 33° / 22° | 76 | 11.9 | 11.9 | 3.2 |
| Oct | 33° / 23° | 137 | 19.5 | 12.2 | 2.8 |
| Nov | 31° / 23° | 199 | 22.9 | 12.5 | 2.8 |
| Dec | 30° / 23° | 246 | 26.3 | 12.6 | 2.9 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Rio Branco gets about 1726 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.
The wetter season lasts 6.7 months, from around Oct 13 to May 5, peaking in February at about 90% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 23.
January is the wettest month by volume, with 255 mm over about 28 wet days; July is the driest, with 21 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 89 | 90 | 87 | 75 | 50 | 24 | 13 | 21 | 40 | 62 | 77 | 84 |
| Rain days | 28 | 25 | 27 | 23 | 15 | 7 | 4 | 6 | 12 | 20 | 23 | 26 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 89 | 28 |
| Feb | 90 | 25 |
| Mar | 87 | 27 |
| Apr | 75 | 23 |
| May | 50 | 15 |
| Jun | 24 | 7 |
| Jul | 13 | 4 |
| Aug | 21 | 6 |
| Sep | 40 | 12 |
| Oct | 62 | 20 |
| Nov | 77 | 23 |
| Dec | 84 | 26 |
Monthly rainfall
Over a full year, Rio Branco collects about 1726 mm of rain across 216 wet days — roughly 144 mm in an average month.
It doesn’t fall evenly. January is the wettest month with 255 mm, while July is the driest at just 21 mm. The three wettest months alone bring about 43% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 255 | 240 | 249 | 160 | 76 | 30 | 21 | 38 | 76 | 137 | 199 | 246 |
| Rain days | 28 | 25 | 27 | 23 | 15 | 7 | 4 | 6 | 12 | 20 | 23 | 26 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 255 | 28 |
| Feb | 240 | 25 |
| Mar | 249 | 27 |
| Apr | 160 | 23 |
| May | 76 | 15 |
| Jun | 30 | 7 |
| Jul | 21 | 4 |
| Aug | 38 | 6 |
| Sep | 76 | 12 |
| Oct | 137 | 20 |
| Nov | 199 | 23 |
| Dec | 246 | 26 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Rio Branco, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around May 15 and lasts for 4.9 months, ending around October 9. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 77% of the time on average.
The cloudier part of the year begins around October 10 and lasts for 7.1 months, ending around May 14. The cloudiest month is February, when it is overcast or mostly cloudy 95% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 6 | 5 | 7 | 15 | 33 | 64 | 77 | 75 | 53 | 26 | 13 | 9 |
| Cloudier (%) | 94 | 95 | 93 | 85 | 67 | 36 | 23 | 25 | 47 | 74 | 87 | 91 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 6 | 94 |
| Feb | 5 | 95 |
| Mar | 7 | 93 |
| Apr | 15 | 85 |
| May | 33 | 67 |
| Jun | 64 | 36 |
| Jul | 77 | 23 |
| Aug | 75 | 25 |
| Sep | 53 | 47 |
| Oct | 26 | 74 |
| Nov | 13 | 87 |
| Dec | 9 | 91 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around January 1, brings about 12 h 36 min of light; the shortest, around June 4, only 11 h 24 min — a swing of roughly 1 h 12 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.5 | 12.3 | 12.1 | 11.8 | 11.5 | 11.4 | 11.5 | 11.7 | 11.9 | 12.2 | 12.5 | 12.6 |
| Sunrise (AM) | 5:25 | 5:36 | 5:39 | 5:38 | 5:41 | 5:49 | 5:53 | 5:45 | 5:27 | 5:10 | 5:03 | 5:10 |
| Sunset (PM) | 5:56 | 5:56 | 5:43 | 5:25 | 5:14 | 5:14 | 5:21 | 5:25 | 5:24 | 5:23 | 5:30 | 5:45 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 12.5 | 5:25 | 5:56 |
| Feb | 12.3 | 5:36 | 5:56 |
| Mar | 12.1 | 5:39 | 5:43 |
| Apr | 11.8 | 5:38 | 5:25 |
| May | 11.5 | 5:41 | 5:14 |
| Jun | 11.4 | 5:49 | 5:14 |
| Jul | 11.5 | 5:53 | 5:21 |
| Aug | 11.7 | 5:45 | 5:25 |
| Sep | 11.9 | 5:27 | 5:24 |
| Oct | 12.2 | 5:10 | 5:23 |
| Nov | 12.5 | 5:03 | 5:30 |
| Dec | 12.6 | 5:10 | 5:45 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Rio Branco averages about 6 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 20 days.
The sunnier stretch runs 4.2 months, from around May 25 to Sep 29. The sunniest month is July, with roughly 18 sunny days (bright).
The greyest month is February, down near 0 sunny days — about 99% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 0 | 0 | 0 | 1 | 5 | 12 | 19 | 17 | 9 | 3 | 1 | 1 |
| Sky | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Mixed | Bright | Bright | Mixed | Gloomy | Gloomy | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 0 | Gloomy |
| Feb | 0 | Gloomy |
| Mar | 0 | Gloomy |
| Apr | 1 | Gloomy |
| May | 5 | Gloomy |
| Jun | 12 | Mixed |
| Jul | 19 | Bright |
| Aug | 17 | Bright |
| Sep | 9 | Mixed |
| Oct | 3 | Gloomy |
| Nov | 1 | Gloomy |
| Dec | 1 | Gloomy |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
Rio Branco is humid all year round — on a typical day the air feels at least humid, and there is no real dry season to wait for.
The stickiest month is January, when it feels muggy, oppressive or miserable about 100% of the time. Even in July, the mildest month, the air is dry or comfortable only 10% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 0 | 0 | 0 | 0 | 0 | 1 | 4 | 4 | 1 | 0 | 0 | 0 |
| Comfortable (%) | 0 | 0 | 0 | 0 | 2 | 2 | 6 | 5 | 3 | 0 | 0 | 0 |
| Humid (%) | 0 | 0 | 0 | 2 | 4 | 7 | 15 | 14 | 5 | 1 | 0 | 0 |
| Muggy (%) | 0 | 0 | 1 | 5 | 13 | 22 | 35 | 29 | 14 | 5 | 2 | 0 |
| Oppressive (%) | 72 | 68 | 63 | 55 | 57 | 65 | 41 | 48 | 75 | 79 | 65 | 69 |
| Miserable (%) | 28 | 32 | 36 | 38 | 23 | 3 | 0 | 0 | 2 | 15 | 32 | 31 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|---|
| Jan | 0 | 0 | 0 | 0 | 72 | 28 |
| Feb | 0 | 0 | 0 | 0 | 68 | 32 |
| Mar | 0 | 0 | 0 | 1 | 63 | 36 |
| Apr | 0 | 0 | 2 | 5 | 55 | 38 |
| May | 0 | 2 | 4 | 13 | 57 | 23 |
| Jun | 1 | 2 | 7 | 22 | 65 | 3 |
| Jul | 4 | 6 | 15 | 35 | 41 | 0 |
| Aug | 4 | 5 | 14 | 29 | 48 | 0 |
| Sep | 1 | 3 | 5 | 14 | 75 | 2 |
| Oct | 0 | 0 | 1 | 5 | 79 | 15 |
| Nov | 0 | 0 | 0 | 2 | 65 | 32 |
| Dec | 0 | 0 | 0 | 0 | 69 | 31 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Wind in Rio Branco is steady company: average speeds sit near 6 km/h — calm — in every month of the year, with no meaningful windy or calm season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 6 | 6 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 6 | calm |
| Feb | 6 | calm |
| Mar | 5 | calm |
| Apr | 5 | calm |
| May | 5 | calm |
| Jun | 6 | calm |
| Jul | 6 | calm |
| Aug | 6 | calm |
| Sep | 6 | calm |
| Oct | 6 | calm |
| Nov | 6 | calm |
| Dec | 6 | calm |
Hazard calendar for Rio Branco
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Rio Branco's rainy season runs October–April, when most of the year's rain falls.
Best time to visit Rio Branco
To characterize how pleasant the weather is in Rio Branco throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late July, Rio Branco is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Rio Branco for general outdoor tourist activities is from mid May to early August, with a peak score in the third week of June.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 2.8 | 2.8 | 2.8 | 3.3 | 4.3 | 5.2 | 5.1 | 4.0 | 3.2 | 2.9 | 2.8 | 2.8 |
| Rating | poor | poor | poor | poor | fair | fair | fair | fair | poor | poor | poor | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 2.8 | poor |
| Feb | 2.8 | poor |
| Mar | 2.8 | poor |
| Apr | 3.3 | poor |
| May | 4.3 | fair |
| Jun | 5.2 | fair |
| Jul | 5.1 | fair |
| Aug | 4.0 | fair |
| Sep | 3.2 | poor |
| Oct | 2.9 | poor |
| Nov | 2.8 | poor |
| Dec | 2.8 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Rio Branco for hot-weather activities is from late May to early September, with a peak score in the third week of July.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Rio Branco, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
Rio Branco packs about the same all year — highs hold near 33°C. Across the year the things worth having are light clothes, rain gear and sun protection.
In September, Rio Branco sees daytime highs around 33°C and nights near 22°C. Pack light clothes. Worth having: rain gear and sun protection. About 12 days see rain.
UV index (midday) in Rio Branco by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Rio Branco peaks around January 20 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near September 12 at about 5 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 15 | 15 | 14 | 13 | 11 | 9 | 8 | 7 | 4 | 12 | 13 | 13 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high | High | Moderate | Extreme | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 15 | Extreme |
| Feb | 15 | Extreme |
| Mar | 14 | Extreme |
| Apr | 13 | Extreme |
| May | 11 | Extreme |
| Jun | 9 | Very high |
| Jul | 8 | Very high |
| Aug | 7 | High |
| Sep | 4 | Moderate |
| Oct | 12 | Extreme |
| Nov | 13 | Extreme |
| Dec | 13 | Extreme |
Average hourly UV index in Rio Branco
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in January the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 7 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 8.5 | 8.5 | 8 | 8 | 7.5 | 7 | 6.5 | 6 | 5 | 8 | 8.5 | 8.5 |
| UV ≥ 6 (h/day) | 7 | 7 | 6.5 | 6 | 5.5 | 4.5 | 4 | 2 | 0 | 6 | 6.5 | 6.5 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 8.5 | 7 |
| Feb | 8.5 | 7 |
| Mar | 8 | 6.5 |
| Apr | 8 | 6 |
| May | 7.5 | 5.5 |
| Jun | 7 | 4.5 |
| Jul | 6.5 | 4 |
| Aug | 6 | 2 |
| Sep | 5 | 0 |
| Oct | 8 | 6 |
| Nov | 8.5 | 6.5 |
| Dec | 8.5 | 6.5 |
Air quality in Rio Branco by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.
Air quality in Rio Branco is worst in September — around 100 µg/m³ PM2.5 (unhealthy), about 12.4× the cleanest month (June, 8 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 13 | 13 | 13 | 10 | 8 | 8 | 14 | 65 | 100 | 27 | 13 | 11 |
| Level | Moderate | Moderate | Moderate | Good | Good | Good | Moderate | Unhealthy | Unhealthy | Moderate | Moderate | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 13 | Moderate |
| Feb | 13 | Moderate |
| Mar | 13 | Moderate |
| Apr | 10 | Good |
| May | 8 | Good |
| Jun | 8 | Good |
| Jul | 14 | Moderate |
| Aug | 65 | Unhealthy |
| Sep | 100 | Unhealthy |
| Oct | 27 | Moderate |
| Nov | 13 | Moderate |
| Dec | 11 | Good |
Growing season
Rio Branco is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 0 |
| Mar | 100 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 100 | 0 |
| Dec | 100 | 0 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Rio Branco banks about 6,005 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around September.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 511 | 460 | 509 | 488 | 484 | 459 | 478 | 517 | 530 | 545 | 509 | 516 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 511 |
| Feb | 460 |
| Mar | 509 |
| Apr | 488 |
| May | 484 |
| Jun | 459 |
| Jul | 478 |
| Aug | 517 |
| Sep | 530 |
| Oct | 545 |
| Nov | 509 |
| Dec | 516 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Rio Branco receives about 4.9 kWh/m² a day of solar energy — bright — and it stays remarkably steady, holding between 4.2 and 5.6 kWh/m² all year. For solar panels, output here is a flat line, not a seasonal wave.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.8 | 4.6 | 4.6 | 4.4 | 4.3 | 4.3 | 4.8 | 5.3 | 5.6 | 5.5 | 5.1 | 4.9 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 4.8 | Bright |
| Feb | 4.6 | Bright |
| Mar | 4.6 | Bright |
| Apr | 4.4 | Bright |
| May | 4.3 | Bright |
| Jun | 4.3 | Bright |
| Jul | 4.8 | Bright |
| Aug | 5.3 | Bright |
| Sep | 5.6 | Bright |
| Oct | 5.5 | Bright |
| Nov | 5.1 | Bright |
| Dec | 4.9 | Bright |
Where is Rio Branco?
Rio Branco sits at 10.0°S, 67.8°W, 153 m above sea level, in Brazil. The nearest listed city is Senador Guiomard, 21 km away.
Topography around Rio Branco
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Rio Branco.
Within 3 km, the terrain around Rio Branco has only modest variations in elevation — a maximum elevation change of 50 m around an average of 142 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 103 m; within 80 km, only modest variations in elevation — a maximum elevation change of 165 m.
The land around Rio Branco is covered by artificial surfaces (54%) and trees (33%) within 3 km, trees (46%) and grassland (46%) within 16 km, and trees (61%) and grassland (38%) within 80 km.
Brazil travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type C / N
- 127 / 220 V · 60 Hz
- Prices
- ≈ 46% of US
- price level, 2025
- GDP per capita
- $10,713
- 2025
- Happiness
- 6.6 / 10
- World Happiness, 2025
- Safe drinking water
- 89%
- of population, 2024
- Homicide rate
- 19.3
- per 100k, 2023
- Road deaths
- 16
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Low
- EF EPI 482
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Rio Branco (-9.9747°, -67.81°, elevation 153 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).