Climate averages 1991–2020
Itaboraí weather
in September.
A warm, moderately wet month: the 8th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Itaboraí: daytime highs average 25.9°C and nights cool to about 17.4°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 82 mm of rain on roughly 11 days, which makes September a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 57 min on an average September day.
The nearest other city in this atlas is Maricá (20 km away). In September its highs average 26.0°C, about as warm as Itaboraí, with 61 mm of rain.
Among the 448 cities listed in Brazil, Itaboraí ranks joint 300th of 448 for the warmest September highs and joint 292nd of 448 for the driest September (rainfall, lowest first). The mean September high of those 448 cities is 27.5°C; Itaboraí is 1.6°C cooler than that mean.
From September to October, average highs rise by 1.1°C to 27.0°C, and monthly rainfall rises from 82 mm to 112 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Itaboraí climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 29.7°C22.5°C | 22.5°C | 259 | 21.3 | 13.413 h |
| February | 30.1°C22.5°C | 22.5°C | 203 | 18.2 | 12.913 h |
| March | 28.6°C21.8°C | 21.8°C | 220 | 21.7 | 12.212 h |
| April | 27.0°C20.1°C | 20.1°C | 108 | 14.2 | 11.612 h |
| May | 24.8°C17.5°C | 17.5°C | 77 | 10.9 | 11.011 h |
| June | 24.4°C16.1°C | 16.1°C | 44 | 6.9 | 10.811 h |
| July | 24.1°C15.4°C | 15.4°C | 44 | 7.3 | 10.911 h |
| August | 24.9°C15.8°C | 15.8°C | 43 | 7.4 | 11.311 h |
| September, selected | 25.9°C17.4°C | 17.4°C | 82 | 11.1 | 11.912 h |
| October | 27.0°C19.1°C | 19.1°C | 112 | 13.4 | 12.613 h |
| November | 27.0°C20.1°C | 20.1°C | 210 | 18.7 | 13.213 h |
| December | 28.7°C21.6°C | 21.6°C | 255 | 21.6 | 13.513 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Maricá in SeptemberBrazil · 20 kmHigh 26.0°C · Low 19.2°C · 61 mm rain
- Magé in SeptemberBrazil · 21 kmHigh 26.3°C · Low 17.6°C · 85 mm rain
- São Gonçalo in SeptemberBrazil · 22 kmHigh 26.3°C · Low 18.1°C · 85 mm rain
- Rio de Janeiro in SeptemberBrazil · 38 kmHigh 26.8°C · Low 18.6°C · 75 mm rain
- Teresópolis in SeptemberBrazil · 38 kmHigh 23.0°C · Low 14.6°C · 102 mm rain
- Petrópolis in SeptemberBrazil · 42 kmHigh 23.8°C · Low 15.1°C · 88 mm rain
- Saquarema in SeptemberBrazil · 43 kmHigh 24.5°C · Low 19.3°C · 58 mm rain
- Duque de Caxias in SeptemberBrazil · 47 kmHigh 27.1°C · Low 18.2°C · 86 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Itaboraí) is explained once on the Itaboraí year overview and on the Sources, method and limits page.