September weather forecast and climate
Lisbon, Portugal

The beautiful hillside city of Lisbon in Portugal, with a high, far view of the Sao Jorge Castle
The beautiful hillside city of Lisbon in Portugal, with a high, far view of the Sao Jorge Castle
The first month of the autumn, September, is still a warm month in Lisbon, Portugal, with temperature in the range of an average high of 26.5°C (79.7°F) and an average low of 17.6°C (63.7°F).

Temperature

In September, the average high-temperature is essentially the same as in August - a still warm 26.5°C (79.7°F). In September, the average low-temperature is 17.6°C (63.7°F).

Rainfall

In September, the rain falls for 6 days. Throughout September, 32.9mm (1.3") of precipitation is accumulated. Throughout the year, there are 112 rainfall days, and 774mm (30.47") of precipitation is accumulated.

Sea temperature

September is the month with the warmest seawater in Lisbon, with an average sea temperature of 19.9°C (67.8°F).
Note: Swimming in 19.9°C (67.8°F) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 21°C (69.8°F).

Daylight

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

Sunshine

In Lisbon, the average sunshine in September is 9h.

UV index

The average daily maximum UV index in Lisbon is 6. A UV Index value of 6 to 7 symbolizes a high threat to health from the exposure to the Sun's UV rays for the average person.
Note: In September, the average maximum UV index of 6 translate into the following recommendations:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. 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.

What is the temperature in September in Lisbon?

In September, in Lisbon, Portugal, the average high-temperature is 26.5°C (79.7°F), and the average low-temperature is 17.6°C (63.7°F).

How much does it rain in Lisbon in September?

In Lisbon, during September, the rain falls for 6 days and regularly aggregates up to 32.9mm (1.3") of precipitation.

When is the sea warmest in Lisbon?

The month with the warmest seawater in Lisbon, Portugal, is September, with an average sea temperature of 19.9°C (67.8°F).

What is the sea temperature in September in Lisbon?

In Lisbon, Portugal, in September, the average water temperature is 19.9°C (67.8°F). Swimming in 19.9°C (67.8°F) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 21°C (69.8°F).

What is the average length of the day in September in Lisbon?

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

How many hours of sunshine does Lisbon have in September?

In September, the average sunshine in Lisbon, Portugal, is 9h.

What is the UV index intensity in September in Lisbon?

In Lisbon, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to the UV radiation.
Average temperature in September - Lisbon, Portugal
  • Average high temperature in September: 26.5°C

The warmest month (with the highest average high temperature) is August (28.3°C).
The month with the lowest average high temperature is January (14.8°C).

  • Average low temperature in September: 17.6°C

The month with the highest average low temperature is August (18.6°C).
The coldest month (with the lowest average low temperature) is January (8.3°C).

Average rainfall in September - Lisbon, Portugal
  • Average rainfall in September: 32.9mm

The wettest month (with the highest rainfall) is November (127.6mm).
The driest month (with the least rainfall) is July (4.2mm).

Average rainfall days in September - Lisbon, Portugal
  • Average rainfall days in September: 6 days

Months with the highest number of rainy days are January, February and December (14 days).
Months with the least rainy days are July and August (2 days).

Average sea temperature in September - Lisbon, Portugal
  • Average sea temperature in September: 19.9°C

The best month for swimming (with the highest average sea temperature) is September (19.9°C).
The coldest month (with the lowest average sea temperature) is March (15.1°C).

Average daylight in September / Average sunshine in September - Lisbon, Portugal
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in September: 9h

Months with the most sunshine are July and August (Average sunshine: 11h).
Months with the least sunshine are January, February, November and December (Average sunshine: 5).

Average UV index in September - Lisbon, Portugal
  • Average UV index in September: 6

Months with the highest UV index are June and July (UV index 9).
Months with the lowest UV index are January and December (UV index 2).