Rio Branco Weather in December

NASA POWER reanalysis for the half-degree grid cell around Rio Branco, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

Average highs run from 30°C on December 1 to 29°C on December 31, and lows from 23°C to 23°C. Normal precipitation for the month is 223 mm over about 25 wet days.

December day by day

The normal high and low for each date, in °C.

Normal low
Normal high
Reanalysis extreme high
Reanalysis extreme low

December at a glance

Average high: 29°C
Average low: 23°C
Precipitation: 223 mm
Reanalysis high: 38°CDec 5, 1997
Reanalysis low: 18°CDec 19, 2000
Daylight: 12 h 40 min to 12 h 42 min
Cloud cover: 85%
Humidity: 88%
Dew point: 23°C
Wind: 2.5 km/h

Every day of the month

A wet day has at least 1 mm of precipitation in the reanalysis.

Date	Normal high	Normal low	Reanalysis high	Reanalysis low	Chance wet
Dec 1	30°C	23°C	34°C 1997	21°C 1996	80%
Dec 2	30°C	23°C	34°C 1997	21°C 2001	81%
Dec 3	30°C	23°C	35°C 2017	21°C 2001	81%
Dec 4	30°C	23°C	37°C 1997	21°C 1995	81%
Dec 5	30°C	23°C	38°C 1997	21°C 1996	82%
Dec 6	30°C	23°C	37°C 1997	21°C 1992	83%
Dec 7	29°C	23°C	37°C 1997	21°C 1996	83%
Dec 8	29°C	23°C	38°C 1997	21°C 1999	82%
Dec 9	29°C	23°C	36°C 1997	21°C 1999	82%
Dec 10	29°C	23°C	35°C 2017	22°C 2001	82%
Dec 11	29°C	23°C	37°C 1997	22°C 1996	82%
Dec 12	29°C	23°C	34°C 1997	21°C 1996	82%
Dec 13	29°C	23°C	33°C 1997	21°C 1993	82%
Dec 14	29°C	23°C	36°C 1997	21°C 2010	82%
Dec 15	29°C	23°C	35°C 2020	19°C 2010	83%
Dec 16	29°C	23°C	35°C 1997	21°C 1996	83%
Dec 17	29°C	23°C	36°C 1997	22°C 2007	82%
Dec 18	29°C	23°C	36°C 1997	20°C 2000	82%
Dec 19	29°C	23°C	35°C 2020	18°C 2000	83%
Dec 20	29°C	23°C	36°C 2020	20°C 2000	83%
Dec 21	29°C	23°C	34°C 1997	21°C 2003	83%
Dec 22	29°C	23°C	36°C 1997	21°C 1998	84%
Dec 23	29°C	23°C	36°C 1997	18°C 1998	84%
Dec 24	29°C	23°C	32°C 1997	18°C 1998	85%
Dec 25	29°C	23°C	32°C 1997	20°C 1998	84%
Dec 26	29°C	23°C	32°C 2016	21°C 1999	85%
Dec 27	29°C	23°C	32°C 1997	21°C 2004	86%
Dec 28	29°C	23°C	33°C 1997	20°C 2004	87%
Dec 29	29°C	23°C	34°C 1997	21°C 2007	88%
Dec 30	29°C	23°C	35°C 1997	21°C 2000	88%
Dec 31	29°C	23°C	34°C 1997	21°C 1991	88%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (GMT-5).

December 1: sunrise 5:00 AM, sunset 5:40 PM
December 31: sunrise 5:13 AM, sunset 5:55 PM

Every day of December: sun and moon

Other months

Sources

Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.