Ulianópolis weather in December

In December, Ulianópolis sees average daytime highs of 33°C and overnight lows near 23°C, with 129 mm of rain across 16.8 wet days and about 12.2 hours of daylight. It is the 6th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 33°C in the first days to 32°C by the end. The sky is clear or mostly clear about 9% 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 Ulianópolis's 8th-clearest and 7th-windiest month. For the whole year in context, see Ulianópolis's year-round climate.

Daytime high
33°
6th warmest
Overnight low
23°
10th coldest
Rainfall
129 mm
16.8 wet days
Daylight
12 h 12 min
6:00 AM – 6:13 PM
Cloud cover
74%
8th clearest
Wind
7 km/h
7th windiest
Solar energy
5.2 kWh/m²
Travel score
3.0
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 33°C in the first days to 32°C by the end.

A typical December day in Ulianópolis reaches about 33°C in the afternoon and slips back to 23°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 30°C and 35°C. Set against its neighbours, December runs about 1°C cooler than November and about 2°C warmer than January.

20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
13324
23324
33324
43324
53324
63324
73324
83324
93324
103324
113324
123323
133323
143323
153323
163323
173223
183223
193223
203223
213223
223223
233223
243223
253223
263223
273223
283223
293223
303223
313223

How December really feels in Ulianópolis

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.

Ulianópolis weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 23°23925.812.22.7
Feb30° / 23°27325.712.12.7
Mar30° / 23°34829.2122.6
Apr30° / 23°2472711.92.7
May31° / 23°13119.611.83.4
Jun32° / 22°327.411.84.3
Jul33° / 22°163.611.83.9
Aug35° / 22°61.111.93.4
Sep35° / 23°112123.2
Oct35° / 24°255.612.13.0
Nov34° / 24°6710.212.23.0
Dec33° / 23°12916.812.23.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 9% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 18% of December, with mostly cloudy or overcast conditions the remaining 73%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13763
23664
33664
43664
53664
63565
73466
83367
93367
103268
113268
123070
132971
142971
152773
162674
172575
182476
192476
202377
212278
222278
232278
242080
252080
261981
271981
281981
291882
301882
311882

Chance of precipitation in December

Any precipitation

Ulianópolis gets around 129 mm of rain over 16.8 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 55% and peaks near 73% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
139
239
340
441
541
642
743
844
945
1046
1147
1249
1350
1452
1553
1655
1757
1858
1960
2061
2162
2263
2365
2466
2567
2669
2770
2871
2972
3073
3173

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 88% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
123761
222771
322771
421781
521781
620791
719801
818811
918811
1017821
1116831
1215841
1314851
1412871
1511881
1610891
179901
188911
197921
206931
215932
224942
234942
243952
253952
263952
272953
282953
292953
302953
312953

Wind in December

Winds average 7 km/h in December.

Across December, daily wind ranges from about 6 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
276calm
286calm
296calm
306calm
316calm

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 5:54 AM to 6:07 AM, and sunset from 6:06 PM to 6:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:546:06
212.25:546:06
312.25:546:07
412.25:556:07
512.25:556:07
612.25:556:08
712.25:566:08
812.25:566:09
912.25:576:09
1012.25:576:10
1112.25:576:10
1212.25:586:11
1312.25:586:11
1412.25:596:12
1512.25:596:12
1612.26:006:13
1712.26:006:13
1812.26:016:14
1912.26:016:14
2012.26:026:15
2112.26:026:15
2212.26:026:15
2312.26:036:16
2412.26:036:16
2512.26:046:17
2612.26:046:17
2712.26:056:18
2812.26:056:18
2912.26:066:19
3012.26:066:19
3112.26:076:20

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.2 kWh/m².

For context, solar energy here swings from a low near 4.18 kWh/m² to a high of 6.15 kWh/m² in October across the year — December's 5.2 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.5Bright
85.4Bright
95.4Bright
105.4Bright
115.3Bright
125.3Bright
135.3Bright
145.3Bright
155.2Bright
165.2Bright
175.1Bright
185.1Bright
195.1Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
244.9Bright
254.9Bright
264.9Bright
274.9Bright
284.8Bright
294.8Bright
304.8Bright
314.8Bright
Planning a trip in December

Hazard calendar for Ulianópolis

In seasonPeak

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

Ulianópolis's monsoon runs January–April, 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 Ulianópolis?

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

3.0
Sightseeing
6th-best month of the year
5.1
Beach & pool
8th-best month of the year

December is a weaker month for outdoor sightseeing in Ulianópolis.

What to pack for Ulianópolis in December

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

In December, Ulianópolis sees daytime highs around 33°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 17 days see rain.

light clothesrain gearsun protection

UV index in Ulianópolis in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

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

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeMar 15UV 15Jul 17UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May11Extreme
Jun10Extreme
Jul10Extreme
Aug10Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec10Extreme

Air quality in Ulianópolis 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 Ulianópolis is worst in November — around 33 µg/m³ PM2.5 (moderate), about 3.7× the cleanest month (June, 9 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateNov 2033 µg/m³Jun 139 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb16Moderate
Mar15Moderate
Apr12Moderate
May10Good
Jun9Good
Jul11Good
Aug13Moderate
Sep16Moderate
Oct21Moderate
Nov33Moderate
Dec30Moderate
Location & terrain

Where is Ulianópolis?

Ulianópolis sits at 3.7°S, 47.5°W, 119 m above sea level, in Brazil. The nearest listed city is Dom Eliseu, 60 km away.

Topography around Ulianópolis

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

Within 3 km, the terrain around Ulianópolis has only modest variations in elevation — a maximum elevation change of 47 m around an average of 113 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 152 m; within 80 km, significant variations in elevation — a maximum elevation change of 304 m.

The land around Ulianópolis is covered by grassland (62%) and trees (26%) within 3 km, grassland (51%) and trees (48%) within 16 km, and trees (65%) and grassland (33%) within 80 km.

3 km
47 m
16 km
152 m
80 km
304 m
treesgrasslandcroplandartificial surfacesbare terrain
December weather nearby: Dom Eliseu 60 km · Itinga do Maranhão 79 km · Paragominas 84 km · Bom Jesus das Selvas 109 km · Rondon do Pará 131 km · Ipixuna do Pará 132 km · Buriticupu 132 km · Açailândia 134 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 Ulianópolis (-3.7419°, -47.4947°, elevation 119 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).