São Mateus do Maranhão weather in December

In December, São Mateus do Maranhão sees average daytime highs of 34°C and overnight lows near 25°C, with 113 mm of rain across 14.3 wet days and about 12.2 hours of daylight. It is the 5th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 35°C in the first days to 33°C by the end. The sky is clear or mostly clear about 17% 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 São Mateus do Maranhão's 8th-clearest and 5th-windiest month. For the whole year in context, see São Mateus do Maranhão's year-round climate.

Daytime high
34°
5th warmest
Overnight low
25°
10th coldest
Rainfall
113 mm
14.3 wet days
Daylight
12 h 12 min
5:47 AM – 6:01 PM
Cloud cover
68%
8th clearest
Wind
8 km/h
5th windiest
Solar energy
5.44 kWh/m²
Travel score
2.6
out of 10

São Mateus do Maranhão is 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

Highs ease over the month, from about 35°C in the first days to 33°C by the end.

A typical December day in São Mateus do Maranhão reaches about 34°C in the afternoon and slips back to 25°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 31°C and 37°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)
13525
23525
33525
43525
53525
63525
73525
83525
93425
103425
113425
123425
133425
143425
153425
163425
173425
183425
193425
203425
213425
223425
233425
243425
253325
263325
273324
283324
293324
303324
313324

How December really feels in São Mateus do Maranhão

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
12 feel dangerously hot (≥ 39°C)
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 Mateus do Maranhão weather by month

How December compares with the rest of the year at a glance. December is the 5th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 24°24224.312.22.6
Feb31° / 24°2632512.12.5
Mar31° / 24°31228.6122.5
Apr31° / 24°27727.111.92.6
May31° / 24°13419.211.83.4
Jun32° / 23°377.611.84.4
Jul33° / 23°183.611.84.3
Aug34° / 24°51.211.93.7
Sep35° / 25°61.1123.0
Oct36° / 25°133.112.12.6
Nov35° / 25°446.812.22.6
Dec34° / 25°11314.312.22.6

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 19% of December, with mostly cloudy or overcast conditions the remaining 64%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14753
24753
34753
44753
54654
64654
74456
84456
94357
104258
114159
124159
133961
143862
153763
163565
173466
183367
193268
203268
213169
223070
232971
242971
252872
262872
272872
282872
292773
302773
312674

Chance of precipitation in December

Any precipitation

São Mateus do Maranhão gets around 113 mm of rain over 14.3 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 46% and peaks near 68% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
129
229
330
430
531
632
733
834
935
1036
1138
1239
1341
1442
1544
1645
1747
1848
1950
2052
2153
2255
2357
2458
2560
2662
2763
2864
2966
3067
3168

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 80% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Muggy (%)Oppressive (%)Miserable (%)
118775
218775
318775
417785
517785
616795
716795
815796
914806
1014806
1113816
1212826
1312826
1411827
1511827
1610837
179838
189838
199838
208839
2188210
2278310
2378211
2478112
2568212
2668113
2768014
2858114
2958015
3058015
3158015

Wind in December

Winds average 8 km/h in December.

Across December, daily wind ranges from about 7 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

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 5:41 AM to 5:54 AM, and sunset from 5:54 PM to 6:08 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:415:54
212.25:415:55
312.25:425:55
412.25:425:55
512.25:435:56
612.25:435:56
712.25:435:57
812.25:445:57
912.25:445:58
1012.25:445:58
1112.25:455:59
1212.25:455:59
1312.25:466:00
1412.25:466:00
1512.25:476:01
1612.25:476:01
1712.25:486:02
1812.25:486:02
1912.25:486:02
2012.25:496:03
2112.25:496:03
2212.25:506:04
2312.25:506:04
2412.25:516:05
2512.25:516:05
2612.25:526:06
2712.25:526:06
2812.25:536:07
2912.25:536:07
3012.25:546:08
3112.25:546:08

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.44 kWh/m².

For context, solar energy here swings from a low near 4.39 kWh/m² to a high of 6.36 kWh/m² in October across the year — December's 5.44 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
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
195.3Bright
205.3Bright
215.3Bright
225.3Bright
235.3Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.1Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in December

Hazard calendar for São Mateus do Maranhão

In seasonPeak

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

São Mateus do Maranhão'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 São Mateus do Maranhão?

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

2.6
Sightseeing
6th-best month of the year
5.2
Beach & pool
7th-best month of the year

December is a weaker month for outdoor sightseeing in São Mateus do Maranhão.

What to pack for São Mateus do Maranhão in December

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

In December, São Mateus do Maranhão sees daytime highs around 34°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 São Mateus do Maranhão 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 São Mateus do Maranhão peaks around March 16 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 24 at about 10 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeMar 16UV 15Jul 24UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr14Extreme
May11Extreme
Jun10Extreme
Jul10Very high
Aug10Very high
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in São Mateus do Maranhão 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 Mateus do Maranhão is worst in October — around 25 µg/m³ PM2.5 (moderate), about 3.0× the cleanest month (June, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateOct 2125 µg/m³Jun 199 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb16Moderate
Mar15Moderate
Apr13Moderate
May10Good
Jun8Good
Jul9Good
Aug12Good
Sep16Moderate
Oct25Moderate
Nov23Moderate
Dec17Moderate
Location & terrain

Where is São Mateus do Maranhão?

São Mateus do Maranhão sits at 4.0°S, 44.5°W, 47 m above sea level, in Brazil. The nearest listed city is Alto Alegre do Maranhão, 19 km away.

Topography around São Mateus do Maranhão

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of São Mateus do Maranhão.

Within 3 km, the terrain around São Mateus do Maranhão has only modest variations in elevation — a maximum elevation change of 28 m around an average of 42 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 76 m; within 80 km, only modest variations in elevation — a maximum elevation change of 174 m.

The land around São Mateus do Maranhão is covered by grassland (44%) and trees (29%) within 3 km, grassland (50%) and trees (31%) within 16 km, and trees (47%) and grassland (46%) within 80 km.

3 km
28 m
16 km
76 m
80 km
174 m
treesshrubsgrasslandcroplandartificial surfaceswaterwetland
December weather nearby: Alto Alegre do Maranhão 19 km · Bacabal 40 km · Coroatá 40 km · Peritoró 41 km · São Luís Gonzaga do Maranhão 43 km · Pirapemas 45 km · Matões do Norte 46 km · Cantanhede 47 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 Mateus do Maranhão (-4.0417°, -44.475°, elevation 47 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).