São João de Meriti weather in December

In December, São João de Meriti sees average daytime highs of 30°C and overnight lows near 22°C, with 237 mm of rain across 21.2 wet days and about 13.4 hours of daylight. It is the 4th-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 29°C in the first days to 31°C by the end. The sky is clear or mostly clear about 14% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 13 h 18 min at the start of December to 13 h 24 min by month's end. Set against the rest of the year, December is São João de Meriti's 11th-clearest and 6th-windiest month. For the whole year in context, see São João de Meriti's year-round climate.

Daytime high
30°
4th warmest
Overnight low
22°
9th coldest
Rainfall
237 mm
21.2 wet days
Daylight
13 h 24 min
6:08 AM – 7:31 PM
Cloud cover
73%
11th clearest
Wind
6 km/h
6th windiest
Solar energy
5.64 kWh/m²
Travel score
3.6
out of 10

São João de Meriti is human settlement in Brazil.

Air quality
Moderate
PM2.5 12 µg/m³ · 2015

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 29°C in the first days to 31°C by the end.

A typical December day in São João de Meriti reaches about 30°C in the afternoon and slips back to 22°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 34°C. Set against its neighbours, December runs about 2°C warmer than November and about 1°C cooler than January.

15°20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
12922
22922
32922
42922
52922
62922
72922
83022
93022
103022
113022
123022
133022
143022
153022
163022
173022
183022
193022
203023
213023
223023
233023
243123
253123
263123
273123
283123
293123
303123
313123

How December really feels in São João de Meriti

Once humidity and wind are folded in, December averages 25 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
25
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.

São João de Meriti weather by month

How December compares with the rest of the year at a glance. December is the 4th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 23°26621.313.23.2
Feb32° / 23°19717.812.83.3
Mar30° / 22°21621.112.23.7
Apr29° / 21°10613.511.55.2
May26° / 18°7411.110.96.6
Jun26° / 17°477.110.67.3
Jul26° / 16°477.210.77.4
Aug26° / 17°447.511.27.2
Sep27° / 18°8711.111.96.3
Oct28° / 20°12014.412.55.3
Nov28° / 21°2131913.14.4
Dec30° / 22°23721.213.43.6

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 14% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 14% of December, with mostly cloudy or overcast conditions the remaining 71%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12674
22674
32575
42575
52476
62476
72476
82575
92674
102674
112674
122773
132971
142971
153070
162971
173070
183169
193169
203268
213268
223367
233367
243367
253268
263169
273169
283169
293070
303070
313070

Chance of precipitation in December

Any precipitation

São João de Meriti gets around 237 mm of rain over 21.2 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 68% and peaks near 74% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
164
264
364
464
564
664
764
865
965
1065
1166
1266
1366
1466
1567
1667
1768
1868
1969
2069
2170
2270
2371
2472
2572
2673
2773
2874
2974
3074
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 68% of days. Sticky, muggy-or-worse air turns up on roughly 96% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1840511
2839521
3738541
4737551
5736561
6635572
7634582
8533602
9532612
10531622
11430642
12429652
13328672
14327682
15326692
16225712
17224722
18224722
19223723
20222733
21221743
22220753
23219763
24218773
25217774
26217774
27216784
28216775
29216775
30116776
31116776

Wind in December

Winds average 6 km/h in December.

Across December, daily wind ranges from about 5 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 13 h 18 min at the start of December to 13 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over December. Sunrise moves from 6:04 AM to 6:15 AM, and sunset from 7:22 PM to 7:38 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.36:047:22
213.36:047:23
313.36:047:24
413.36:057:24
513.36:057:25
613.36:057:25
713.36:057:26
813.46:057:27
913.46:067:27
1013.46:067:28
1113.46:067:29
1213.46:077:29
1313.46:077:30
1413.46:077:30
1513.46:087:31
1613.46:087:31
1713.46:087:32
1813.46:097:32
1913.46:097:33
2013.46:107:34
2113.46:107:34
2213.46:107:34
2313.46:117:35
2413.46:117:35
2513.46:127:36
2613.46:127:36
2713.46:137:37
2813.46:147:37
2913.46:147:37
3013.46:157:38
3113.46:157:38

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.64 kWh/m².

For context, solar energy here swings from a low near 3.33 kWh/m² to a high of 5.93 kWh/m² in February across the year — December's 5.64 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.4Bright
45.4Bright
55.4Bright
65.4Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.5Bright
125.5Bright
135.5Bright
145.6Bright
155.6Bright
165.6Bright
175.6Bright
185.7Bright
195.7Bright
205.7Bright
215.7Bright
225.7Bright
235.7Bright
245.7Bright
255.7Bright
265.7Bright
275.7Bright
285.7Bright
295.7Bright
305.7Bright
315.8Bright
Planning a trip in December

Hazard calendar for São João de Meriti

In seasonPeak

In December, São João de Meriti sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

São João de Meriti's rainy season runs October–March, when most of the year's rain falls.

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

Is December a good time to visit São João de Meriti?

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

3.6
Sightseeing
10th-best month of the year
5.0
Beach & pool
11th-best month of the year

December is a weaker month for outdoor sightseeing in São João de Meriti.

What to pack for São João de Meriti in December

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

In December, São João de Meriti sees daytime highs around 30°C and nights near 22°C. Pack light clothes and rain gear. Worth having: sun protection. About 21 days see rain.

light clothesrain gearsun protection

Sea temperature near São João de Meriti in December

The nearest coast averages about 24°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 36 km away) is warmest in March at about 26°C and coldest in August near 21°C.

The water stays above 20°C all year — warm enough for a swim any month.

20°22°24°26°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan25Warm
Feb25Warm
Mar26Warm
Apr25Warm
May24Refreshing
Jun23Refreshing
Jul22Refreshing
Aug21Refreshing
Sep21Refreshing
Oct22Refreshing
Nov22Refreshing
Dec24Warm

UV index in São João de Meriti in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 14 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in São João de Meriti peaks around January 13 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 13 at about 5 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighExtremeJan 13UV 14Jul 13UV 5
UV index (midday)Level
Jan14Extreme
Feb13Extreme
Mar12Extreme
Apr9Very high
May6High
Jun6High
Jul5Moderate
Aug8Very high
Sep6High
Oct11Extreme
Nov13Extreme
Dec14Extreme

Air quality in São João de Meriti 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 São João de Meriti is worst in July — around 17 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (December, 8 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to São João de Meriti's WHO annual average of 12 µg/m³.

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1217 µg/m³Dec 238 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb8Good
Mar9Good
Apr11Good
May14Moderate
Jun16Moderate
Jul17Moderate
Aug14Moderate
Sep17Moderate
Oct11Good
Nov9Good
Dec8Good
Location & terrain

Where is São João de Meriti?

São João de Meriti sits at 22.8°S, 43.4°W, 14 m above sea level, in Brazil. The nearest listed city is Nilópolis, 4.0 km away.

Topography around São João de Meriti

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of São João de Meriti.

Within 3 km, the terrain around São João de Meriti has only modest variations in elevation — a maximum elevation change of 154 m around an average of 27 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 956 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,224 m.

The land around São João de Meriti is covered by artificial surfaces (88%) within 3 km, artificial surfaces (52%) and trees (28%) within 16 km, and trees (37%), water (31%) and grassland (24%) within 80 km.

3 km
154 m
16 km
956 m
80 km
2,224 m
treesgrasslandartificial surfacesbare terrainwaterwetlandmangroves
December weather nearby: Nilópolis 4.0 km · Belford Roxo 5.0 km · Duque de Caxias 7.0 km · Nova Iguaçu 9.0 km · Queimados 21 km · Estácio 21 km · Barra da Tijuca 22 km · Rio de Janeiro 23 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 São João de Meriti (-22.8039°, -43.3722°, elevation 14 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).