September Weather in Lisbon, United States

Last updated: June 24, 2025

In September, the average temperature in Lisbon, United States is a pleasant 17°C (63°F). Expect a minimum of 3°C (38°F) and a maximum soaring to 31°C (87°F). With an average precipitation of 70 mm (2.8 in) spread over 8 days, the air carries a humidity level of around 71%. Perfect for those who enjoy a bit of everything in their weather!

September Temperature in Lisbon

In September in Lisbon, the average temperature is 17°C (63°F). Maximum temperatures can reach 31°C (87°F), while minimum temperatures can drop to as low as 3°C (38°F). This makes it an ideal time for travelers to enjoy a range of outdoor activities while packing for varying weather conditions.

September Weather in Lisbon: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Lisbon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lisbon, September typically has an average temperature of 17°C (63°F), with highs reaching up to 31°C (87°F) and lows dropping to around 3°C (38°F).

Data source: Temperature data for Lisbon generated using information from the Copernicus Climate Change Service.

September Precipitation in Lisbon

In Lisbon in September, the total precipitation amount is 70 mm (2.8 in), spread over the course of 8 days.

September Precipitation Trends in Lisbon

The chart displays monthly precipitation patterns in Lisbon, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Lisbon, September typically receives around 70 mm (2.8 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Lisbon

In Lisbon in September, humidity is 71%. With an average temperature of 17°C (63°F), this humidity feels like a warm embrace, making outdoor activities enjoyable yet a bit sticky, so travelers should stay hydrated and take breaks in the shade.

September Average Humidity in Lisbon

This chart illustrates the average monthly humidity levels in Lisbon, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Lisbon is approximately 71%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Lisbon

In Lisbon in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Lisbon.

Maximum UV Index Levels in Lisbon for September

The chart shows the monthly maximum UV Index (UVI) for Lisbon in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Lisbon typically reaches 7, which falls under the high exposure category.

Data source: Lisbon September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Lisbon Compares to Other Months

Weather in Lisbon varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Lisbon, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Lisbon, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-4°C (25°F)	83 mm (3.3 inches)	86%	low
February Weather	-3°C (27°F)	87 mm (3.4 inches)	84%	moderate
March Weather	0°C (33°F)	73 mm (2.9 inches)	82%	moderate
April Weather	7°C (44°F)	118 mm (4.7 inches)	80%	high
May Weather	12°C (55°F)	78 mm (3.1 inches)	72%	very high
June Weather	18°C (65°F)	66 mm (2.6 inches)	72%	very high
July Weather	21°C (70°F)	117 mm (4.6 inches)	67%	very high
August Weather	21°C (70°F)	77 mm (3.0 inches)	66%	very high
September Weather	17°C (63°F)	70 mm (2.8 inches)	71%	high
October Weather	11°C (53°F)	131 mm (5.1 inches)	78%	moderate
November Weather	4°C (39°F)	114 mm (4.5 inches)	84%	moderate
December Weather	-2°C (29°F)	120 mm (4.7 inches)	81%	low