September weather forecast and climate
Ribeira da Isna, Portugal

Weather in September

September, the first month of the autumn, in Ribeira da Isna, 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 15.4°C (59.7°F).

Temperature

In Ribeira da Isna, the average high-temperature in September marginally drops, from a hot 32.8°C (91°F) in August, to a warm 28.6°C (83.5°F). The average low-temperature, in Ribeira da Isna, is 15.4°C (59.7°F).

Heat index

In September, the average heat index is evaluated at 29°C (84.2°F). Exhaustion is likely with prolonged exposure and activity. Sustaining activity 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 'felt air temperature', 'feels like', 'real feel', or 'apparent temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is individual, with diverse people perceiving weather differently for numerous reasons (wind, differences in body mass, height, and shape, metabolic differences), and activity. 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. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

In September, the average relative humidity is 49%.

Rainfall

In Ribeira da Isna, in September, during 5.2 rainfall days, 18mm (0.71") of precipitation is typically accumulated. In Ribeira da Isna, Portugal, during the entire year, the rain falls for 97.2 days and collects up to 371mm (14.61") of precipitation.

Snowfall

In Ribeira da Isna snow does not fall in February through December.

Daylight

In Ribeira da Isna, the average length of the day is 12.4h.

Sunshine

In September, the average sunshine in Ribeira da Isna is 9.4h.

UV index

In September, the average daily maximum UV index in Ribeira da Isna, Portugal, is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from the exposure to the Sun's UV rays for the average person.
Note: The daily maximum UV index of 5 in September interpret into the following advice:
Take precautions - Protection against the skin and eye damage is obliged. 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 Ribeira da Isna?

The average high-temperature, in September, is 28.6°C (83.5°F), while the average low-temperature is 15.4°C (59.7°F). The average heat index (a.k.a. 'felt air temperature', 'feels like'), that combines both air temperature and relative humidity, in September is appraised at 29°C (84.2°F).

What is the average humidity in September in Ribeira da Isna?

The average relative humidity in September in Ribeira da Isna is 49%.

How much does it rain in Ribeira da Isna in September?

In Ribeira da Isna, Portugal, in September, during 5.2 rainfall days, 18mm (0.71") of precipitation is typically accumulated.

When it does not snow in Ribeira da Isna?

In Ribeira da Isna snow does not fall in February through December.

What is the average length of the day in September in Ribeira da Isna?

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

How many hours of sunshine does Ribeira da Isna have in September?

The average sunshine in September in Ribeira da Isna, Portugal, is 9.4h.

What is the UV index intensity in September in Ribeira da Isna?

In Ribeira da Isna, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium hazard to health from the exposure to the Sun's UV rays.

Average temperature in September
Ribeira da Isna, Portugal

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

The warmest month (with the highest average high temperature) is August (32.8°C).
The month with the lowest average high temperature is January (11.6°C).

  • Average low temperature in September: 15.4°C

The month with the highest average low temperature is July (17.2°C).
The coldest month (with the lowest average low temperature) is January (3.9°C).

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Average pressure in September
Ribeira da Isna, Portugal

Average pressure in September - Ribeira da Isna, Portugal
  • Average pressure in September: 1016.5mbar

The month with the highest atmospheric pressure is December (1023mbar).
The month with the lowest atmospheric pressure is April (1015.2mbar).

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Average wind speed in September
Ribeira da Isna, Portugal

Average wind speed in September - Ribeira da Isna, Portugal
  • Average wind speed in September: 8.3km/h

The windiest month (with the highest average wind speed) is February (11.3km/h).
The calmest month (with the lowest average wind speed) is September (8.3km/h).

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Average humidity in September
Ribeira da Isna, Portugal

Average humidity in September - Ribeira da Isna, Portugal
  • Average humidity in September: 49%

The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is August (44%).

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Average rainfall in September
Ribeira da Isna, Portugal

Average rainfall in September - Ribeira da Isna, Portugal
  • Average rainfall in September: 18mm

The wettest month (with the highest rainfall) is November (60mm).
The driest months (with the least rainfall) are July and August (3mm).

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Average rainfall days in September
Ribeira da Isna, Portugal

Average rainfall days in September - Ribeira da Isna, Portugal
  • Average rainfall days in September: 5.2 days

The month with the highest number of rainy days is November (12.3 days).
The month with the least rainy days is August (1.5 days).

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Average snowfall in September
Ribeira da Isna, Portugal

Average snowfall in September - Ribeira da Isna, Portugal
  • Average snowfall in September: 0mm

The month with the highest snowfall is January (1mm).
Months with the least snowfall are February, March, April, May, June, July, August, September, October, November and December (0mm).

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Average snowfall days in September
Ribeira da Isna, Portugal

Average snowfall days in September - Ribeira da Isna, Portugal
  • Average snowfall days in September: 0 days

Months with the highest number of snowfall days are January and March (0.1 days).
Months with the least snowfall days are February, April, May, June, July, August, September, October, November and December (0 days).

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Average daylight in September /
Average sunshine in September
Ribeira da Isna, Portugal

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

The month with the longest days is June (Average daylight: 15h).
The month with the shortest days is December (Average daylight: 9.4h).

  • Average sunshine in September: 9.4h

Months with the most sunshine are July and August (Average sunshine: 11.8h).
The month with the least sunshine is January (Average sunshine: 5.2h).

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Average sunshine days in September
Ribeira da Isna, Portugal

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

The month with the most sunshine days is August (28.3 days).
The month with the least sunshine days is April (16.6 days).

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Average UV index in September
Ribeira da Isna, Portugal

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

Months with the highest UV index are May, June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 2).

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Average cloud cover in September
Ribeira da Isna, Portugal

Average cloud cover in September - Ribeira da Isna, Portugal
  • Average cloud cover in September: 17

The month with the most cloud cover is January (Cloud cover 42).
Months with the least cloud cover are July and August (Cloud cover 8).

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Average visibility in September
Ribeira da Isna, Portugal

Average visibility in September - Ribeira da Isna, Portugal
  • Average visibility in September: 10km

Months with the highest visibility are June, July, August and September (10km).
The month with the lowest visibility is January (8km).

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