São Sebastião in Summer
In summer (December, January and February), São Sebastião sees average daytime highs around 28°C and overnight lows near 19°C, with 587 mm of rain over about 62 wet days across the season. It is the 2nd-warmest season and the wettest season of the year.
Across summer, daytime highs hold fairly steady around 28°C. The sky is clear or mostly clear about 13% of the time across summer, and the air most often feels muggy.
Summer is São Sebastião's weakest season of the year to visit on our travel score. For the whole year in context, see São Sebastião's year-round climate.
- Avg daytime high
- 28°C
- 2nd-warmest season
- Avg overnight low
- 19°C
- Rainfall
- 587 mm
- 62 wet days
- Avg wind
- 7 km/h
- Travel score
- 4.6
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in São Sebastião in Summer
Across summer, daytime highs hold fairly steady around 28°C.
A typical summer day in São Sebastião reaches about 28°C and drops to 19°C overnight. The warmest of the three months is February, the coolest January.
São Sebastião weather by month
How the three summer months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 28° / 19° | 203 | 21 | 12.8 | 4.6 |
| Feb | 28° / 19° | 160 | 18.2 | 12.5 | 4.8 |
| Mar | 28° / 19° | 181 | 20.1 | 12.1 | 4.8 |
| Apr | 28° / 18° | 71 | 11.3 | 11.7 | 6.1 |
| May | 27° / 16° | 17 | 3.2 | 11.3 | 7.7 |
| Jun | 27° / 14° | 4 | 0.6 | 11.1 | 8.4 |
| Jul | 27° / 14° | 0 | 0 | 11.1 | 8.6 |
| Aug | 29° / 15° | 5 | 1.2 | 11.5 | 7.5 |
| Sep | 30° / 18° | 28 | 4.8 | 11.9 | 5.6 |
| Oct | 30° / 19° | 104 | 13.3 | 12.4 | 4.6 |
| Nov | 28° / 19° | 201 | 21.2 | 12.7 | 4.3 |
| Dec | 28° / 19° | 225 | 23.2 | 12.9 | 4.3 |
Cloud cover in Summer
The sky is clear or mostly clear about 13% of the time across summer.
Chance of precipitation in Summer
São Sebastião gets around 587 mm of rain over 62 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 7 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 12 h 54 min in early December to 12 h 24 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.6 kWh/m².
Hazard calendar for São Sebastião
In summer, São Sebastião overlaps its monsoon season. The full year is below, with each hazard's peak months called out.
São Sebastião's monsoon runs October–March, when most of the year's rain falls.
Is summer a good time to visit São Sebastião?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit São Sebastião for sightseeing.
What to pack for São Sebastião in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, São Sebastião sees daytime highs around 28°C and nights near 19°C. Pack light clothes and rain gear. Worth having: sun protection. About 62 days see rain.
UV index in São Sebastião in Summer
Clear-sky midday UV across summer averages around 15 (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 15 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 23 at about 8 (very high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 15 | 16 | 15 | 12 | 10 | 8 | 8 | 10 | 13 | 13 | 15 | 13 |
| Level | Extreme | Extreme | Extreme | Extreme | Very high | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 15 | Extreme |
| Feb | 16 | Extreme |
| Mar | 15 | Extreme |
| Apr | 12 | Extreme |
| May | 10 | Very high |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 10 | Very high |
| Sep | 13 | Extreme |
| Oct | 13 | Extreme |
| Nov | 15 | Extreme |
| Dec | 13 | Extreme |
Air quality in São Sebastião in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in São Sebastião is worst in September — around 32 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (January, 11 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 11 | 13 | 15 | 14 | 15 | 13 | 13 | 15 | 32 | 21 | 13 | 12 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 11 | Good |
| Feb | 13 | Moderate |
| Mar | 15 | Moderate |
| Apr | 14 | Moderate |
| May | 15 | Moderate |
| Jun | 13 | Moderate |
| Jul | 13 | Moderate |
| Aug | 15 | Moderate |
| Sep | 32 | Moderate |
| Oct | 21 | Moderate |
| Nov | 13 | Moderate |
| Dec | 12 | Moderate |
Where is São Sebastião?
São Sebastião sits at 15.9°S, 47.8°W, 1,048 m above sea level, in Brazil. The nearest listed city is Jardim Botânico, 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 only modest variations in elevation — a maximum elevation change of 233 m around an average of 968 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 343 m; within 80 km, large variations in elevation — a maximum elevation change of 779 m.
The land around São Sebastião is covered by grassland (34%), artificial surfaces (31%) and trees (23%) within 3 km, grassland (39%), trees (24%) and shrubs (21%) within 16 km, and grassland (34%), trees (25%) and cropland (22%) within 80 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
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 (-15.9029°, -47.7761°, elevation 1,048 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.