Viana weather in December

In December, Viana sees average daytime highs of 33°C and overnight lows near 25°C, with 91 mm of rain across 14 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 33°C through the month. The sky is clear or mostly clear about 19% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of December to 12 h 12 min by month's end. Set against the rest of the year, December is Viana's 7th-clearest and 4th-windiest month. For the whole year in context, see Viana's year-round climate.

Daytime high
33°
4th warmest
Overnight low
25°
11th coldest
Rainfall
91 mm
14 wet days
Daylight
12 h 12 min
5:51 AM – 6:02 PM
Cloud cover
66%
7th clearest
Wind
11 km/h
4th windiest
Solar energy
5.45 kWh/m²
Travel score
3.1
out of 10

Viana is human settlement in Brazil.

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 33°C through the month.

A typical December day in Viana reaches about 33°C in the afternoon and slips back to 25°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 35°C. Set against its neighbours, December runs about 1°C cooler than November and about 1°C warmer than January.

20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
13425
23425
33425
43325
53325
63325
73325
83325
93325
103325
113325
123325
133325
143325
153325
163325
173325
183325
193325
203325
213325
223325
233325
243325
253325
263325
273325
283325
293225
303225
313225

How December really feels in Viana

Once humidity and wind are folded in, December averages 31 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in December is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Viana weather by month

How December compares with the rest of the year at a glance. December is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 25°20524.412.22.7
Feb31° / 24°27925.512.12.5
Mar31° / 24°35529.5122.4
Apr31° / 24°36728.211.92.4
May31° / 25°20223.411.93.0
Jun31° / 24°7914.511.83.9
Jul32° / 24°5010.111.84.4
Aug33° / 24°153.911.94.2
Sep34° / 25°92123.7
Oct34° / 25°183.512.13.3
Nov34° / 25°396.612.13.3
Dec33° / 25°911412.23.1

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 19% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 60%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14951
24951
34951
44951
54852
64951
74852
84753
94654
104654
114555
124456
134456
144357
154258
164159
173862
183763
193763
203565
213565
223466
233367
243268
253268
263169
273070
282971
292971
302872
312773

Chance of precipitation in December

Any precipitation

Viana gets around 91 mm of rain over 14 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 45% and peaks near 65% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
127
228
328
429
530
631
732
833
934
1036
1137
1239
1340
1442
1544
1645
1747
1849
1950
2052
2153
2255
2356
2457
2558
2660
2761
2862
2963
3064
3165

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the oppressive band about 79% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
118712
218712
318712
418712
518712
618613
718613
818613
908614
1008614
1108515
1208515
1308416
1408317
1508218
1608119
1708020
1807921
1907822
2007723
2107525
2207426
2307327
2407129
2507030
2606931
2706832
2806733
2906733
3006634
3106634

Wind in December

Winds average 11 km/h in December.

Across December, daily wind ranges from about 10 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
112calm
212calm
312calm
412calm
512calm
612calm
712calm
812calm
912calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3010calm
3110calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 12 h 12 min at the start of December to 12 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 0 minutes over December. Sunrise moves from 5:45 AM to 5:58 AM, and sunset from 5:55 PM to 6:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:455:55
212.25:455:55
312.25:455:56
412.25:465:56
512.25:465:57
612.25:465:57
712.25:475:58
812.25:475:58
912.25:485:58
1012.25:485:59
1112.25:485:59
1212.25:496:00
1312.25:496:00
1412.25:506:01
1512.25:506:01
1612.25:516:02
1712.25:516:02
1812.25:526:03
1912.25:526:03
2012.25:526:04
2112.25:536:04
2212.25:536:05
2312.25:546:05
2412.25:546:06
2512.25:556:06
2612.25:556:06
2712.25:566:07
2812.25:566:07
2912.25:576:08
3012.25:576:08
3112.25:586:09

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.45 kWh/m².

For context, solar energy here swings from a low near 4.22 kWh/m² to a high of 6.22 kWh/m² in October across the year — December's 5.45 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.7Bright
45.7Bright
55.7Bright
65.7Bright
75.7Bright
85.6Bright
95.6Bright
105.6Bright
115.6Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.4Bright
175.4Bright
185.4Bright
195.4Bright
205.3Bright
215.3Bright
225.3Bright
235.3Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.2Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in December

Hazard calendar for Viana

In seasonPeak

None of Viana's seasonal hazards are active in December. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Viana's monsoon runs January–May, when most of the year's rain falls.

Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Viana?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.1
Sightseeing
7th-best month of the year
5.5
Beach & pool
7th-best month of the year

December is a weaker month for outdoor sightseeing in Viana.

What to pack for Viana in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Viana sees daytime highs around 33°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 14 days see rain.

light clothesrain gearsun protection

UV index in Viana in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Viana peaks around March 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 15 at about 10 (extreme).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 17UV 15Jul 15UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May11Extreme
Jun10Extreme
Jul10Very high
Aug10Extreme
Sep12Extreme
Oct12Extreme
Nov10Extreme
Dec11Extreme

Air quality in Viana in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Viana is worst in November — around 18 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (June, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateNov 1918 µg/m³Jun 199 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb17Moderate
Mar16Moderate
Apr14Moderate
May10Good
Jun9Good
Jul9Good
Aug10Good
Sep9Good
Oct13Moderate
Nov18Moderate
Dec16Moderate
Location & terrain

Where is Viana?

Viana sits at 3.2°S, 45.0°W, 13 m above sea level, in Brazil. The nearest listed city is Cajari, 11 km away.

Topography around Viana

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Viana.

Within 3 km, the terrain around Viana has only modest variations in elevation — a maximum elevation change of 30 m around an average of 6 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 55 m; within 80 km, only modest variations in elevation — a maximum elevation change of 169 m.

The land around Viana is covered by water (38%), wetland (25%) and grassland (20%) within 3 km, grassland (47%), wetland (22%) and trees (21%) within 16 km, and grassland (41%) and trees (38%) within 80 km.

3 km
30 m
16 km
55 m
80 km
169 m
treesgrasslandcroplandartificial surfaceswaterwetlandmangroves
December weather nearby: Cajari 11 km · Matinha 14 km · Penalva 21 km · Vitória do Mearim 31 km · Arari 36 km · São João Batista 37 km · São Vicente Ferrer 39 km · Monção 41 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
Roman Catholic 57%Evangelical 27%none 9%other 4%

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 Viana (-3.2203°, -45.0036°, elevation 13 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).