September weather forecast
Java, São Tomé and Príncipe

September

Weather in September

As September unfolds, the weather in Java, São Tomé and Príncipe, commences its transition into the wetter season. This change is evidenced by the rise in rainfall to 35mm (1.38"), from a mere 21mm (0.83") the previous month. Despite the increase in precipitation, the wind speed remains high. September brings an increase in cloud cover, slightly reducing the amount of sunshine the city receives. Regardless, the steady wind and modest rainfall make it suitable for exploring the vibrant city life.

Temperature

During September, Java records an average high-temperature of a still moderately hot 25.5°C (77.9°F), marking a slight divergence from August's 24.8°C (76.6°F). Java consistently logs a low temperature averaging a still warm 24.6°C (76.3°F) during September, a modest drop from daytime temperatures.

Humidity

August through October, with an average relative humidity of 83%, are the most humid months.

Rainfall

In Java, in September, during 15.8 rainfall days, 35mm (1.38") of precipitation is typically accumulated. In Java, during the entire year, the rain falls for 241.7 days and collects up to 1287mm (50.67") of precipitation.

Daylight

In September, the average length of the day is 12h and 7min.
On the first day of the month, sunrise is at 05:29 and sunset at 17:36. On the last day of September, sunrise is at 05:19 and sunset at 17:26 GMT.

Sunshine

The average sunshine in September in Java is 5.4h.

UV index

In September, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: The maximum daily UV index of 6 in September converts into the following recommendations:
Adopt measures and apply sun safety strategies. Shielding from skin and eye damage is necessary. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Boost your sun resistance with garments that are densely woven yet spacious.

Frequently asked questions

What is the temperature in September in Java?
September temperatures in Java, São Tomé and Príncipe, vary between a high-temperature of 25.5°C (77.9°F) and a low-temperature of 24.6°C (76.3°F). In May, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines relative humidity and air temperature, is evaluated at 31°C (87.8°F).
What is the most humid month in Java?
The months with the highest humidity in Java are August through October, with an average relative humidity of 83%.
What is the average humidity in September in Java?
In Java, São Tomé and Príncipe, the average relative humidity in September is 83%.
How many days does it rain in September in Java?
In Java, in September, during 15.8 rainfall days, 35mm (1.38") of precipitation is typically accumulated.
What is the average length of the day in September in Java?
In Java, São Tomé and Príncipe, the average day length in September is 12h and 7min.
When is the sunrise / sunset in September in Java?
On the first day of September, sunrise is at 05:29 and sunset at 17:36. On the last day of the month, sunrise is at 05:19 and sunset at 17:26 GMT.
How many hours of sunshine does Java have in September?
In Java, São Tomé and Príncipe, the average sunshine duration in September is 5.4h.
What is the UV index intensity in September in Java?
The average daily maximum UV index in September in Java, São Tomé and Príncipe, is 6. A UV Index estimate of 6 to 7 represents a high health threat from unprotected exposure to UV radiation.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in September - Java, São Tomé and Príncipe
Average temperature in September
Java, São Tomé and Príncipe
  • Average high temperature in September: 25.5°C

The warmest month (with the highest average high temperature) is March (28.8°C).
The month with the lowest average high temperature is July (24.5°C).

  • Average low temperature in September: 24.6°C

The month with the highest average low temperature is March (27.5°C).
The coldest month (with the lowest average low temperature) is July (23°C).

Average pressure in September - Java, São Tomé and Príncipe
Average pressure in September
Java, São Tomé and Príncipe
  • Average pressure in September: 1013.1mbar

The month with the highest atmospheric pressure is July (1014.3mbar).
The month with the lowest atmospheric pressure is February (1009.8mbar).

Average wind speed in September - Java, São Tomé and Príncipe
Average wind speed in September
Java, São Tomé and Príncipe
  • Average wind speed in September: 16.8km/h

The windiest month (with the highest average wind speed) is July (17.7km/h).
The calmest month (with the lowest average wind speed) is December (10.8km/h).

Average humidity in September - Java, São Tomé and Príncipe
Average humidity in September
Java, São Tomé and Príncipe
  • Average humidity in September: 83%

The months with the highest relative humidity are August, September and October (83%).
The month with the lowest relative humidity is March (76%).

Average rainfall in September - Java, São Tomé and Príncipe
Average rainfall in September
Java, São Tomé and Príncipe
  • Average rainfall in September: 35mm

The wettest month (with the highest rainfall) is November (224mm).
The driest month (with the least rainfall) is July (9mm).

Average rainfall days in September - Java, São Tomé and Príncipe
Average rainfall days in September
Java, São Tomé and Príncipe
  • Average rainfall days in September: 15.8 days

The month with the highest number of rainy days is December (28.6 days).
The month with the least rainy days is June (7.3 days).

Average daylight in September / Average sunshine in September - Java, São Tomé and Príncipe
Average daylight in September /
Average sunshine in September
Java, São Tomé and Príncipe
  • Average daylight in September: 12h and 1min

The month with the longest days is June (Average daylight: 12h and 6min).
The month with the shortest days is November (Average daylight: 12h and 6min).

  • Average sunshine in September: 5h and 2min

The month with the most sunshine is February (Average sunshine: 8h and 36min).
The month with the least sunshine is August (Average sunshine: 5h and 0min).

Average sunshine days in September - Java, São Tomé and Príncipe
Average sunshine days in September
Java, São Tomé and Príncipe
  • Average sunshine days in September: 5.3 days

The month with the most sunshine days is June (16.4 days).
The month with the least sunshine days is December (1.5 days).

Average UV index in September - Java, São Tomé and Príncipe
Average UV index in September
Java, São Tomé and Príncipe
  • Average UV index in September: 6

The months with the highest UV index are January, February, March, April, May, October, November and December (UV index 7).
The month with the lowest UV index is July (UV index 5).

Average cloud cover in September - Java, São Tomé and Príncipe
Average cloud cover in September
Java, São Tomé and Príncipe
  • Average cloud cover in September: 62

The month with the most cloud cover is August (Cloud cover 65).
The month with the least cloud cover is February (Cloud cover 37).

Average visibility in September - Java, São Tomé and Príncipe
Average visibility in September
Java, São Tomé and Príncipe
  • Average visibility in September: 10km

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

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