São Sebastião weather in December

In December, São Sebastião sees average daytime highs of 26°C and overnight lows near 22°C, with 214 mm of rain across 19.2 wet days and about 13.4 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Highs climb over the month, from about 25°C in the first days to 27°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 24 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 Sebastião's 10th-clearest and 6th-windiest month. For the whole year in context, see São Sebastião's year-round climate.

Daytime high
26°
4th warmest
Overnight low
22°
9th coldest
Rainfall
214 mm
19.2 wet days
Daylight
13 h 30 min
6:14 AM – 7:42 PM
Cloud cover
72%
10th clearest
Wind
10 km/h
6th windiest
Solar energy
5.9 kWh/m²
Travel score
5.1
out of 10

São Sebastião 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 climb over the month, from about 25°C in the first days to 27°C by the end.

A typical December day in São Sebastião reaches about 26°C in the afternoon and slips back to 22°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 29°C. Set against its neighbours, December runs about 2°C warmer than November and about 1°C cooler than January.

15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12522
22522
32522
42522
52522
62522
72522
82522
92522
102522
112522
122622
132622
142622
152622
162622
172622
182623
192623
202623
212623
222623
232623
242623
252623
262723
272723
282723
292723
302723
312723

São Sebastião weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 24°27722.413.34.6
Feb27° / 24°22819.612.84.7
Mar27° / 23°23620.612.25.0
Apr25° / 22°13013.711.56.2
May23° / 20°11512.110.96.6
Jun23° / 18°829.510.67.0
Jul22° / 18°928.810.77.0
Aug22° / 18°758.911.27.0
Sep22° / 19°13213.711.96.1
Oct23° / 20°14715.212.65.8
Nov24° / 21°18717.513.15.6
Dec26° / 22°21419.213.45.1

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 72%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12872
22773
32674
42575
52575
62575
72575
82575
92575
102773
112773
122773
132872
142872
152872
162872
172971
183070
192971
203070
213169
223169
233268
243169
253070
263070
273070
282872
292872
302872
312872

Chance of precipitation in December

Any precipitation

São Sebastião gets around 214 mm of rain over 19.2 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 63% 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 (%)
157
257
358
458
558
659
759
860
960
1060
1161
1261
1362
1463
1563
1663
1764
1864
1964
2064
2164
2264
2364
2465
2565
2666
2766
2867
2967
3068
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 57% of days. Sticky, muggy-or-worse air turns up on roughly 92% of them.

0%25%50%75%100%151015202531
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
121343411
221342431
321241441
411241451
511240471
611139481
711138491
811137501
901036531
1001035541
1101034542
120933562
130932572
140832573
150831583
160830593
170729604
180728614
190727615
200727615
210626626
220625636
230525637
240524647
250523648
260423658
270422659
280422659
290421669
3003216610
3103216610

Wind in December

Winds average 10 km/h in December.

Across December, daily wind ranges from about 9 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm
319calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 13 h 24 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 0 minutes over December. Sunrise moves from 6:11 AM to 6:21 AM, and sunset from 7:32 PM to 7:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.46:117:32
213.46:117:33
313.46:117:34
413.46:117:34
513.46:117:35
613.46:117:36
713.46:117:36
813.46:127:37
913.46:127:37
1013.46:127:38
1113.46:127:39
1213.46:137:39
1313.46:137:40
1413.56:137:40
1513.56:147:41
1613.56:147:42
1713.56:147:42
1813.56:157:43
1913.56:157:43
2013.56:167:44
2113.56:167:44
2213.56:177:45
2313.56:177:45
2413.56:187:46
2513.56:187:46
2613.56:197:46
2713.56:197:47
2813.56:207:47
2913.56:207:48
3013.56:217:48
3113.46:217:48

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 5.9 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 3.22 kWh/m² to a high of 5.9 kWh/m² in December across the year — December's 5.9 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.8Bright
35.8Bright
45.8Bright
55.8Bright
65.8Bright
75.8Bright
85.8Bright
95.8Bright
105.8Bright
115.8Bright
125.8Bright
135.8Bright
145.8Bright
155.9Bright
165.9Bright
175.9Bright
185.9Bright
195.9Bright
205.9Bright
215.9Bright
225.9Bright
235.9Bright
245.9Bright
255.9Bright
265.9Bright
275.9Bright
285.9Bright
295.8Bright
305.8Bright
315.8Bright
Planning a trip in December

Is December a good time to visit São Sebastião?

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

5.1
Sightseeing
9th-best month of the year
4.9
Beach & pool
5th-best month of the year

December is a reasonable time to visit São Sebastião for sightseeing.

What to pack for São Sebastião in December

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

In December, São Sebastião sees daytime highs around 26°C and nights near 22°C. Pack rain gear. Worth having: light clothes and sun protection. About 19 days see rain.

rain gearlight clothessun protection

Sea temperature near São Sebastião in December

The nearest coast averages about 25°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 25 km away) is warmest in February at about 27°C and coldest in August near 21°C.

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

20°25°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan26Warm
Feb27Warm
Mar27Warm
Apr26Warm
May24Refreshing
Jun22Refreshing
Jul21Refreshing
Aug21Refreshing
Sep21Refreshing
Oct22Refreshing
Nov23Refreshing
Dec25Warm

UV index in São Sebastião 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 Sebastião peaks around February 8 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 11 at about 5 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighVery highExtremeFeb 8UV 14Jul 11UV 5
UV index (midday)Level
Jan14Extreme
Feb14Extreme
Mar11Extreme
Apr9Very high
May7High
Jun6High
Jul5High
Aug8Very high
Sep8Very high
Oct11Extreme
Nov13Extreme
Dec14Extreme

Air quality in São Sebastião 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 Sebastião is worst in June — around 23 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (November, 13 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateJun 2223 µg/m³Nov 2313 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb13Moderate
Mar13Moderate
Apr14Moderate
May18Moderate
Jun23Moderate
Jul23Moderate
Aug22Moderate
Sep21Moderate
Oct16Moderate
Nov13Moderate
Dec13Moderate
Location & terrain

Where is São Sebastião?

São Sebastião sits at 23.8°S, 45.4°W, 6 m above sea level, in Brazil. The nearest listed city is Ilhabela, 6.0 km away.

Topography around São Sebastião

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

Within 3 km, the terrain around São Sebastião has large variations in elevation — a maximum elevation change of 806 m around an average of 181 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,359 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,647 m.

The land around São Sebastião is covered by trees (50%) and water (39%) within 3 km, trees (53%) and water (36%) within 16 km, and water (53%) and trees (33%) within 80 km.

3 km
806 m
16 km
1,359 m
80 km
1,647 m
treesgrasslandartificial surfaceswater
December weather nearby: Ilhabela 6.0 km · Caraguatatuba 16 km · Paraibuna 49 km · Ubatuba 50 km · Salesópolis 52 km · Biritiba Mirim 67 km · Guararema 74 km · Bertioga 75 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 Sebastião (-23.76°, -45.4097°, elevation 6 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).