São Luís weather in December

In December, São Luís sees average daytime highs of 28°C and overnight lows near 26°C, with 73 mm of rain across 15.3 wet days and about 12.1 hours of daylight. It is the 7th-warmest and 8th-wettest month of the year here.

Day-to-day highs hold fairly steady near 28°C through the month. The sky is clear or mostly clear about 33% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 12 h 06 min at the start of December to 12 h 06 min by month's end. Set against the rest of the year, December is São Luís's 7th-clearest and 4th-windiest month. For the whole year in context, see São Luís's year-round climate.

Daytime high
28°
7th warmest
Overnight low
26°
9th coldest
Rainfall
73 mm
15.3 wet days
Daylight
12 h 06 min
5:49 AM – 5:58 PM
Cloud cover
58%
7th clearest
Wind
20 km/h
4th windiest
Solar energy
5.77 kWh/m²
Travel score
5.2
out of 10

São Luís 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 28°C through the month.

A typical December day in São Luís reaches about 28°C in the afternoon and slips back to 26°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 29°C. Set against its neighbours, December runs on par with November and on par with January.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12926
22926
32926
42926
52826
62826
72826
82826
92826
102826
112826
122826
132826
142826
152826
162826
172826
182826
192826
202826
212826
222826
232826
242826
252826
262826
272826
282826
292826
302826
312826

How December really feels in São Luís

Once humidity and wind are folded in, December averages 9 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
9
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 Luís weather by month

How December compares with the rest of the year at a glance. December is the 7th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 25°22125.412.14.0
Feb28° / 25°3032612.13.6
Mar27° / 25°44030.3123.4
Apr28° / 25°41428.811.93.4
May28° / 26°28626.911.93.7
Jun28° / 26°1532311.94.2
Jul29° / 26°1032011.94.7
Aug29° / 26°28911.96.1
Sep29° / 26°113.2127.0
Oct28° / 26°133.612.16.9
Nov29° / 26°276.812.16.3
Dec28° / 26°7315.312.15.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% 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 49%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15941
26040
35941
45941
55941
65842
75842
85842
95743
105743
115644
125644
135545
145446
155347
165248
175149
185050
194852
204753
214852
224654
234555
244555
254456
264357
274357
284258
294258
304159
314060

Chance of precipitation in December

Any precipitation

São Luís gets around 73 mm of rain over 15.3 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 49% and peaks near 69% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
129
230
330
431
532
633
734
836
937
1038
1140
1242
1344
1446
1548
1650
1752
1854
1956
2058
2159
2261
2362
2463
2564
2665
2766
2867
2968
3068
3169

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
Oppressive (%)Miserable (%)
18416
28416
38416
48416
58317
68317
78317
88218
98218
108119
118020
128020
137921
147822
157822
167723
177723
187624
197624
207624
217624
227624
237624
247624
257723
267723
277822
287822
297921
308020
318020

Wind in December

Winds average 20 km/h in December.

Across December, daily wind ranges from about 18 km/h on the calmest days to 21 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
121breezy
221breezy
321breezy
421breezy
521breezy
621breezy
721breezy
821breezy
921breezy
1021breezy
1121breezy
1221breezy
1321breezy
1421breezy
1520breezy
1620breezy
1720breezy
1820breezy
1920breezy
2020breezy
2120light breeze
2220light breeze
2320light breeze
2420light breeze
2519light breeze
2619light breeze
2719light breeze
2819light breeze
2919light breeze
3019light breeze
3118light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 12 h 06 min at the start of December to 12 h 06 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 5:43 AM to 5:56 AM, and sunset from 5:51 PM to 6:05 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.15:435:51
212.15:435:51
312.15:445:52
412.15:445:52
512.15:445:53
612.15:455:53
712.15:455:54
812.15:465:54
912.15:465:54
1012.15:465:55
1112.15:475:55
1212.15:475:56
1312.15:485:56
1412.15:485:57
1512.15:495:57
1612.15:495:58
1712.15:495:58
1812.15:505:59
1912.15:505:59
2012.15:516:00
2112.15:516:00
2212.15:526:01
2312.15:526:01
2412.15:536:02
2512.15:536:02
2612.15:546:02
2712.15:546:03
2812.15:556:03
2912.15:556:04
3012.15:566:04
3112.15:566:05

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.77 kWh/m².

For context, solar energy here swings from a low near 4.57 kWh/m² to a high of 6.4 kWh/m² in October across the year — December's 5.77 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.0Intense
26.0Bright
36.0Bright
46.0Bright
56.0Bright
66.0Bright
75.9Bright
85.9Bright
95.9Bright
105.9Bright
115.9Bright
125.8Bright
135.8Bright
145.8Bright
155.8Bright
165.8Bright
175.7Bright
185.7Bright
195.7Bright
205.7Bright
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.5Bright
275.5Bright
285.5Bright
295.5Bright
305.5Bright
315.5Bright
Planning a trip in December

Hazard calendar for São Luís

In seasonPeak

None of São Luís'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 Luís'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 São Luís?

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

5.2
Sightseeing
5th-best month of the year
6.1
Beach & pool
5th-best month of the year

December is a reasonable time to visit São Luís for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for São Luís in December

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

In December, São Luís sees daytime highs around 28°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection and a windbreaker. About 15 days see rain.

light clothesrain gearsun protectiona windbreaker

Sea temperature near São Luís in December

The nearest coast averages about 28°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 13 km away) is warmest in May at about 29°C and coldest in October near 28°C.

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

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan28Tropical
Feb28Tropical
Mar28Tropical
Apr29Tropical
May29Tropical
Jun29Tropical
Jul28Tropical
Aug28Tropical
Sep28Warm
Oct28Warm
Nov28Warm
Dec28Warm

UV index in São Luís 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 Luís peaks around March 17 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 17UV 15Jul 17UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar16Extreme
Apr14Extreme
May12Extreme
Jun10Extreme
Jul10Very high
Aug10Extreme
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in São Luís 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 Luís is worst in February — around 18 µg/m³ PM2.5 (moderate), about 2.7× the cleanest month (July, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodFeb 2018 µg/m³Jul 157 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb18Moderate
Mar18Moderate
Apr13Moderate
May8Good
Jun7Good
Jul7Good
Aug8Good
Sep9Good
Oct10Good
Nov10Good
Dec11Good
Location & terrain

Where is São Luís?

São Luís sits at 2.5°S, 44.3°W, 29 m above sea level, in Brazil. The nearest listed city is Alcântara, 19 km away.

Topography around São Luís

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

Within 3 km, the terrain around São Luís has only modest variations in elevation — a maximum elevation change of 37 m around an average of 8 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 65 m; within 80 km, only modest variations in elevation — a maximum elevation change of 102 m.

The land around São Luís is covered by artificial surfaces (38%) and water (33%) within 3 km, water (52%) and trees (20%) within 16 km, and water (36%) and trees (35%) within 80 km.

3 km
37 m
16 km
65 m
80 km
102 m
treesshrubsgrasslandartificial surfacesbare terrainwaterwetlandmangroves
December weather nearby: Alcântara 19 km · Paço do Lumiar 22 km · Raposa 25 km · São José de Ribamar 27 km · Icatu 38 km · Rosário 46 km · Morros 47 km · Bacabeira 49 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 Luís (-2.5297°, -44.3028°, elevation 29 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).