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Rio Branco, Brazil climate

Am Tropical monsoon

Rio Branco has a remarkably steady tropical climate (Tropical monsoon, Köppen Am). The hottest month is October with an average daily high near 33°C, while the coldest is July averaging around 18°C at night. Precipitation totals about 2011 mm a year and is strongly seasonal — February alone averages 299 mm while July barely receives 28 mm.

☀️ All year

Hot

Daytime highs near 33°C most of the year.

🌙 Nights

Stays warm

Even the coolest nights stay near 18°C.

🌧️ Rain

Very wet

About 2011 mm of rain a year.

Wettest in February

⛅ Sky & trend

Often cloudy

Cloudy skies much of the year.

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Hours of sunshine per day

Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)

Rio Branco climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	31	31	31	31	31	31	32	33	34	33	32	31
Avg temp (°C)	26	26	26	26	25	24	24	25	—	26	26	26
Avg low (°C)	23	23	23	22	21	19	18	19	21	22	23	23
Precipitation (mm)	286	299	286	204	99	45	28	57	94	144	209	261

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°C)	31	31	31	31	31	31
Avg temp (°C)	26	26	26	26	25	24
Avg low (°C)	23	23	23	22	21	19
Precipitation (mm)	286	299	286	204	99	45

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°C)	32	33	34	33	32	31
Avg temp (°C)	24	25	—	26	26	26
Avg low (°C)	18	19	21	22	23	23
Precipitation (mm)	28	57	94	144	209	261

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	87	87	85	76	66	52	41	49	63	77	82	85
Relative humidity (%)	92	92	93	92	91	89	82	72	70	75	84	90
Wind speed (mph)	0.2	0.2	0.2	0.2	0.3	0.3	0.3	0.3	0.2	0.1	0.1	0.1

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	87	87	85	76	66	52
Relative humidity (%)	92	92	93	92	91	89
Wind speed (mph)	0.2	0.2	0.2	0.2	0.3	0.3

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	41	49	63	77	82	85
Relative humidity (%)	82	72	70	75	84	90
Wind speed (mph)	0.3	0.3	0.2	0.1	0.1	0.1

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from INMET, Brazil's national meteorological institute, measured at Rio Branco, about 1 km from the city centre.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →