Rio Negro Weather in December

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

Average highs run from 33°C on December 1 to 32°C on December 31, and lows from 23°C to 23°C. Normal precipitation for the month is 179 mm over about 21 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: 32°C
Average low: 23°C
Precipitation: 179 mm
Reanalysis high: 41°CDec 20, 2020
Reanalysis low: 13°CDec 2, 2001
Daylight: 13 h 13 min to 13 h 18 min
Cloud cover: 75%
Humidity: 73%
Dew point: 21°C
Wind: 10.4 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	33°C	23°C	38°C 2020	16°C 2001	63%
Dec 2	33°C	23°C	38°C 2020	13°C 2001	65%
Dec 3	33°C	23°C	39°C 2011	17°C 2018	66%
Dec 4	32°C	23°C	39°C 2020	16°C 2008	66%
Dec 5	32°C	23°C	39°C 2010	19°C 2008	66%
Dec 6	32°C	23°C	38°C 2008	19°C 2001	66%
Dec 7	32°C	23°C	39°C 2008	20°C 2000	66%
Dec 8	32°C	23°C	37°C 2020	19°C 2005	67%
Dec 9	32°C	23°C	39°C 2020	18°C 2003	66%
Dec 10	32°C	23°C	39°C 2020	18°C 2003	65%
Dec 11	32°C	23°C	37°C 2011	20°C 2004	64%
Dec 12	32°C	23°C	36°C 2020	19°C 2017	63%
Dec 13	32°C	23°C	37°C 2020	17°C 2010	63%
Dec 14	32°C	23°C	38°C 2004	15°C 2010	64%
Dec 15	32°C	23°C	37°C 2004	17°C 2011	65%
Dec 16	32°C	23°C	36°C 2018	18°C 2000	65%
Dec 17	32°C	23°C	37°C 2018	13°C 2000	65%
Dec 18	32°C	23°C	38°C 2020	18°C 2000	64%
Dec 19	32°C	22°C	41°C 2020	17°C 1998	64%
Dec 20	32°C	23°C	41°C 2020	18°C 2000	65%
Dec 21	32°C	23°C	39°C 2020	18°C 2007	65%
Dec 22	32°C	23°C	37°C 2011	19°C 1998	65%
Dec 23	32°C	23°C	37°C 1999	17°C 1998	66%
Dec 24	32°C	23°C	38°C 2020	20°C 2001	68%
Dec 25	32°C	23°C	39°C 2020	21°C 1993	70%
Dec 26	32°C	23°C	40°C 2020	22°C 1991	72%
Dec 27	32°C	23°C	37°C 2011	20°C 2007	72%
Dec 28	32°C	23°C	38°C 2002	20°C 2004	72%
Dec 29	32°C	23°C	38°C 2008	21°C 1995	71%
Dec 30	32°C	23°C	38°C 2002	20°C 1993	71%
Dec 31	32°C	23°C	38°C 2002	17°C 1993	72%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (GMT-4).

December 1: sunrise 4:53 AM, sunset 6:06 PM
December 31: sunrise 5:04 AM, sunset 6:22 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 2026-09-26. Sun and moon: computed with the NOAA solar equations and Meeus.