September weather forecast and climate
São João da Ribeira, Portugal

Weather in September

September, the first month of the autumn, in São João da Ribeira, is still a warm month, with temperature in the range of an average high of 28.6°C (83.5°F) and an average low of 15.2°C (59.4°F).

Temperature

In September, the average high-temperature is essentially the same as in August - a moderately hot 28.6°C (83.5°F). The average low-temperature, in September, is 15.2°C (59.4°F).

Heat index

The average heat index is evaluated at a hot 30.8°C (87.4°F). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'feels like', 'apparent temperature', or 'felt air temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. Additional factors like pregnancy, clothing, metabolic differences, and activity influence one's weather impression. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

In São João da Ribeira, the average relative humidity is 63%.

Rainfall

In São João da Ribeira, in September, during 5.7 rainfall days, 19mm (0.75") of precipitation is typically accumulated. In São João da Ribeira, during the entire year, the rain falls for 108.1 days and collects up to 337mm (13.27") of precipitation.

Daylight

In September, the average length of the day is 12.4h.

Sunshine

In September, the average sunshine is 9.3h.

UV index

In São João da Ribeira, Portugal, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from the exposure to the Sun's UV radiation for the ordinary person.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in São João da Ribeira?

The average high-temperature, in September, in São João da Ribeira, is 28.6°C (83.5°F), while the average low-temperature is 15.2°C (59.4°F). In September, the average heat index (a.k.a. 'real feel', 'feels like'), that combines relative humidity and air temperature, is evaluated at 30.8°C (87.4°F).

What is the average humidity in September in São João da Ribeira?

In São João da Ribeira, Portugal, the average relative humidity in September is 63%.

How many days does it rain in September in São João da Ribeira?

In São João da Ribeira, Portugal, in September, it is raining for 5.7 days, with typically 19mm (0.75") of accumulated precipitation.

How many hours of daylight does São João da Ribeira have in September?

In September, the average length of the day in São João da Ribeira is 12.4h.

How long on average sun shines in September in São João da Ribeira?

The average sunshine in September in São João da Ribeira, Portugal, is 9.3h.

How high is the UV index in September in São João da Ribeira?

The average daily maximum UV index in September in São João da Ribeira, Portugal, is 5. A UV Index of 3 to 5 symbolizes a medium health risk from unprotected exposure to the UV radiation.

Average temperature in September
São João da Ribeira, Portugal

Average temperature in September - São João da Ribeira, Portugal
  • Average high temperature in September: 28.6°C

The warmest month (with the highest average high temperature) is August (31°C).
The month with the lowest average high temperature is January (14°C).

  • Average low temperature in September: 15.2°C

The month with the highest average low temperature is July (15.8°C).
The coldest months (with the lowest average low temperature) are January and February (6.8°C).

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Average pressure in September
São João da Ribeira, Portugal

Average pressure in September - São João da Ribeira, Portugal
  • Average pressure in September: 1016.7mbar

The month with the highest atmospheric pressure is December (1022.6mbar).
The month with the lowest atmospheric pressure is April (1015.5mbar).

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Average wind speed in September
São João da Ribeira, Portugal

Average wind speed in September - São João da Ribeira, Portugal
  • Average wind speed in September: 10.6km/h

The windiest month (with the highest average wind speed) is July (13.2km/h).
The calmest months (with the lowest average wind speed) are September and October (10.6km/h).

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Average humidity in September
São João da Ribeira, Portugal

Average humidity in September - São João da Ribeira, Portugal
  • Average humidity in September: 63%

The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is August (62%).

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Average rainfall in September
São João da Ribeira, Portugal

Average rainfall in September - São João da Ribeira, Portugal
  • Average rainfall in September: 19mm

The wettest month (with the highest rainfall) is November (53mm).
The driest months (with the least rainfall) are July and August (3mm).

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Average rainfall days in September
São João da Ribeira, Portugal

Average rainfall days in September - São João da Ribeira, Portugal
  • Average rainfall days in September: 5.7 days

The month with the highest number of rainy days is November (13.9 days).
The month with the least rainy days is August (2.4 days).

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Average daylight in September /
Average sunshine in September
São João da Ribeira, Portugal

Average daylight in September / Average sunshine in September - São João da Ribeira, Portugal
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.9h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in September: 9.3h

The month with the most sunshine is July (Average sunshine: 11.2h).
The month with the least sunshine is January (Average sunshine: 5.2h).

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Average sunshine days in September
São João da Ribeira, Portugal

Average sunshine days in September - São João da Ribeira, Portugal
  • Average sunshine days in September: 23.3 days

The month with the most sunshine days is July (27.3 days).
Months with the least sunshine days are April and November (14.6 days).

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Average UV index in September
São João da Ribeira, Portugal

Average UV index in September - São João da Ribeira, Portugal
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
São João da Ribeira, Portugal

Average cloud cover in September - São João da Ribeira, Portugal
  • Average cloud cover in September: 21

The month with the most cloud cover is January (Cloud cover 42).
The month with the least cloud cover is August (Cloud cover 17).

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Average visibility in September
São João da Ribeira, Portugal

Average visibility in September - São João da Ribeira, Portugal
  • Average visibility in September: 9km

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

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