UV and heat in São Paulo
In São Paulo, the average daily peak UV index stays at 3 or above in every month of the year, from 4.5 in June to 10.2 in January.
The warmest month is February, with average highs of 29°C, and the air is most humid in March, at around 83% relative humidity. UV figures come from five years of NASA satellite data, 2020 to 2024, and temperatures from the nearest long-running weather station.
- 10.2Average daily peak UV in January, very high
- 12Months with an average peak of UV 3 or more
- 29°CAverage high in February
- 7.5 hA day at UV 3 or more in January, on average
When is the UV index highest in São Paulo?
The sun is strongest all year round, with the highest average peak in January. In January, about 85% of days reach a UV index of 8 or more, which the World Health Organization calls very high.
How hot and humid does São Paulo get?
Average highs range from 23°C to 29°C through the year. Relative humidity averages 67% to 83%. Day length ranges from 10.7 to 13.6 hours.
Month by month
| Month | Peak UV | Days UV 8+ | Hours UV 3+ | High | Low | Humidity | Daylight |
|---|---|---|---|---|---|---|---|
| January | 10.2 | 85% | 7.5 | 29°C | 20°C | 81% | 13.4 h |
| February | 9.8 | 84% | 7.2 | 29°C | 20°C | 82% | 12.9 h |
| March | 9.5 | 85% | 6.9 | 28°C | 20°C | 83% | 12.2 h |
| April | 7.6 | 58% | 6.0 | 26°C | 18°C | 81% | 11.5 h |
| May | 5.6 | 3% | 5.0 | 23°C | 15°C | 77% | 11.0 h |
| June | 4.5 | 0% | 4.0 | 23°C | 14°C | 78% | 10.7 h |
| July | 5.0 | 0% | 4.4 | 23°C | 13°C | 73% | 10.8 h |
| August | 5.9 | 12% | 5.0 | 24°C | 13°C | 70% | 11.3 h |
| September | 6.8 | 45% | 5.4 | 26°C | 16°C | 67% | 12.0 h |
| October | 7.3 | 49% | 6.0 | 26°C | 17°C | 76% | 12.6 h |
| November | 9.5 | 81% | 7.3 | 26°C | 18°C | 74% | 13.3 h |
| December | 10.0 | 87% | 7.6 | 28°C | 19°C | 77% | 13.6 h |
When should you protect your skin in São Paulo?
The World Health Organization advises sun protection whenever the UV index is 3 or above, and the advice gets stronger from 8. In São Paulo, that means every month of the year, for about 7.5 hours around midday in January. The forecast on any day can be higher or lower than these averages, so check it each morning.
How do you protect yourself?
Cancer Council Australia recommends five steps together when the UV index is 3 or higher: slip on covering clothing, slop on SPF 50 or SPF50+ broad-spectrum, water-resistant sunscreen, slap on a hat, seek shade and slide on some sunglasses.
Clothing covers skin all day without reapplying. Sleeves usually stop at the wrist and the collar, so the backs of your hands and your neck are easy to miss; the Meriggio · Italian · say it “meh-REED-joh”The shady spot where you rest through the midday heat. has hand covers and a neck shade for those two places. Women’s fit, men’s fit.
Other cities in Brazil
UV and heat across Brazil. All cities.
Sources and data
- UV index: NASA POWER Hourly API, NASA Langley Research Center, CERES SYN1deg (UV index), MERRA-2 (temperature, humidity). Hourly values for 2020 to 2024, around -23.55, -46.63. Satellite and reanalysis grid values for the area around the city, not a single weather station. Peak UV is the mean of each day’s highest hourly UV index. Fetched 18 October 2026.
- Temperature: NOAA NCEI Global Surface Summary of the Day, weather station CAMPO DE MARTE (83779099999), 4.6 km from the city centre, 2010 to 2024. Highs and lows are the average of each month’s mean daily maximum and minimum.
- Relative humidity is an area average from NASA POWER for a grid square about 55 km wide.
- Day length calculated from latitude for the 15th of each month.
- World Health Organization: Radiation, the ultraviolet (UV) index, 20 June 2022
- Cancer Council Australia: Be SunSmart