September weather - Spring 2024 - Rio de Janeiro, Brazil

Weather in September
Frequently asked questions
Average temperature in September
Average pressure in September
Average wind speed in September
Average humidity in September
Average rainfall in September
Average rainfall days in September
Average sea temperature in September
Average daylight in September
Average sunshine in September
Average sunshine days in September
Average UV index in September
Average cloud cover in September
Average visibility in September

Christ the Redeemer statue atop Mount Corcovado, overlooking the seaside city of Rio de Janeiro, Brazil

Weather in September

September signifies the arrival of spring in Rio de Janeiro, holding promises of new beginnings and renewed vitality. Witnessing an increase in rainfall to 47mm (1.85"), an indicator that the dry season has ended, still doesn't interfere with outdoor plans significantly. Generally speaking, temperature goes back to the mid-twenties on average, signaling the forthcoming summer. Despite the climb in humidity, the weather stays within comfortable limits for most outdoor ventures. While it is a reminder of the summer humidity to come, it also brings with it excitement for the festive season ahead.

Temperature

The transition into September is marked with an average high-temperature of a still warm 25°C (77°F), showing an insignificant shift from August's 24.3°C (75.7°F). Rio de Janeiro anticipates an average minimum temperature of 19.4°C (66.9°F) in the month of September.

Humidity

In Rio de Janeiro, the average relative humidity in September is 78%.

Rainfall

In Rio de Janeiro, in September, during 13.7 rainfall days, 47mm (1.85") of precipitation is typically accumulated. In Rio de Janeiro, Brazil, during the entire year, the rain falls for 192.5 days and collects up to 812mm (31.97") of precipitation.

Sea temperature

September is the month with the coldest seawater in Rio de Janeiro, with an average sea temperature of 21.6°C (70.9°F).
Note: Swimming is not a pleasurable activity for the majority in water at 21.6°C (70.9°F). Breathing control gets harder as the water temperature dips from 21°C (69.8°F) to 15°C (59°F).

Daylight

The average length of the day in September is 11h and 58min.
On the first day of September in Rio de Janeiro, Brazil, sunrise is at 06:02 and sunset at 17:42. On the last day of the month, sunrise is at 05:33 and sunset at 17:51 -03.

Sunshine

In September, the average sunshine in Rio de Janeiro is 7.9h.

UV index

The month with the lowest UV index in Rio de Janeiro is September, with an average maximum UV index of 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Take necessary precautions - Suggestions to elude sunburn are provided. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Warning! Reflective surfaces like sand and water amplify the Sun's UV radiation.

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Frequently asked questions

What are September temperatures in Rio de Janeiro?

In September, in Rio de Janeiro, the average high-temperature is 25°C (77°F), and the average low-temperature is 19.4°C (66.9°F). In March, the average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, is estimated at 33°C (91.4°F).

What is the average humidity in September in Rio de Janeiro?

In Rio de Janeiro, the average relative humidity in September is 78%.

How much does it rain in Rio de Janeiro in September?

In September, the rain falls for 13.7 days. Throughout September, 47mm (1.85") of precipitation is accumulated.

What month is the sea coldest in Rio de Janeiro?

September is the month with the coldest seawater in Rio de Janeiro, with an average sea temperature of 21.6°C (70.9°F).

How cold is the water in September in Rio de Janeiro?

In Rio de Janeiro, Brazil, in September, the average water temperature is 21.6°C (70.9°F). For swimming, a surface water temperature of 21.6°C (70.9°F) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 21°C (69.8°F).

How many hours of daylight does Rio de Janeiro have in September?

In September, the average day length in Rio de Janeiro is 11h and 58min.

What time are sunrise and sunset in September in Rio de Janeiro?

On the first day of September in Rio de Janeiro, Brazil, sunrise is at 06:02 and sunset at 17:42. On the last day of the month, sunrise is at 05:33 and sunset at 17:51 -03.

How many hours of sunshine does Rio de Janeiro have in September?

The average sunshine duration in September is 7.9h.

What is the month with the lowest UV index in Rio de Janeiro?

September is the month with the lowest UV index, with an average maximum UV index of 5.

How high is the UV index in September in Rio de Janeiro?

The average daily maximum UV index in September in Rio de Janeiro is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

24.3°C 75.7°F

25°C 77°F

26.3°C 79.3°F

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

12.3km/h 7.6mph

11.9km/h 7.4mph

12.4km/h 7.7mph

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

10.4

13.7

18.3

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

19.3

14.3

9.8

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Rio de Janeiro, Brazil

Average high temperature in September: 25°C

The warmest month (with the highest average high temperature) is February (29.7°C).
The month with the lowest average high temperature is July (24°C).

Average low temperature in September: 19.4°C

The month with the highest average low temperature is January (23.7°C).
The coldest month (with the lowest average low temperature) is August (18.5°C).

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Average pressure in September
Rio de Janeiro, Brazil

Average pressure in September: 1017.8mbar

The month with the highest atmospheric pressure is July (1020.5mbar).
The month with the lowest atmospheric pressure is December (1011.9mbar).

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Average wind speed in September
Rio de Janeiro, Brazil

Average wind speed in September: 11.3km/h

The windiest months (with the highest average wind speed) are August and September (11.3km/h).
The calmest month (with the lowest average wind speed) is March (8.7km/h).

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Average humidity in September
Rio de Janeiro, Brazil

Average humidity in September: 78%

The month with the highest relative humidity is November (82%).
The month with the lowest relative humidity is August (76%).

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Average rainfall in September
Rio de Janeiro, Brazil

Average rainfall in September: 47mm

The wettest month (with the highest rainfall) is November (119mm).
The driest month (with the least rainfall) is June (29mm).

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Average rainfall days in September
Rio de Janeiro, Brazil

Average rainfall days in September: 13.7 days

The month with the highest number of rainy days is March (22.7 days).
The month with the least rainy days is July (9.3 days).

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Average sea temperature in September
Rio de Janeiro, Brazil

Average sea temperature in September: 21.6°C

The best month for swimming (with the highest average sea temperature) is March (25.8°C).
The coldest month (with the lowest average sea temperature) is September (21.6°C).

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Average daylight in September /
Average sunshine in September
Rio de Janeiro, Brazil

Average daylight in September: 12h and 0min

The month with the longest days is December (Average daylight: 13h and 30min).
The month with the shortest days is June (Average daylight: 10h and 48min).

Average sunshine in September: 7h and 5min

The month with the most sunshine is February (Average sunshine: 8h and 48min).
The month with the least sunshine is October (Average sunshine: 7h and 30min).

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Average sunshine days in September
Rio de Janeiro, Brazil

Average sunshine days in September: 14.3 days

The month with the most sunshine days is July (20.6 days).
The month with the least sunshine days is December (4.8 days).

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Average UV index in September
Rio de Janeiro, Brazil

Average UV index in September: 5

The month with the highest UV index is January (UV index 7).
The month with the lowest UV index is September (UV index 5).

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Average cloud cover in September
Rio de Janeiro, Brazil

Average cloud cover in September: 34

The month with the most cloud cover is November (Cloud cover 46).
The month with the least cloud cover is February (Cloud cover 28).

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Average visibility in September
Rio de Janeiro, Brazil

Average visibility in September: 10km

The months with the highest visibility are February, May, June, July, August and September (10km).
The months with the lowest visibility are January, March, April, October, November and December (9km).

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September weather forecast
Rio de Janeiro, Brazil

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