September Weather in Lisbon, United States

Last updated: June 24, 2025

In September, the average temperature in Lisbon, United States is a pleasant 19°C (67°F), making it an ideal time for outdoor activities. However, be prepared for temperature variations, as it can drop to a chilly 2°C (36°F) and rise to a warm 34°C (93°F). Expect approximately 130 mm (5.1 in) of precipitation spread over 9 days, and don't forget to stay hydrated, as the average humidity hovers around 78%. Enjoy your time in this vibrant location!

September Temperature in Lisbon

In September in Lisbon, the average temperature is 19°C (67°F). Maximums can reach 34°C (93°F), while minimums can be as low as 2°C (36°F). Pack accordingly to enjoy a range of outdoor activities in this diverse climate!

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 19°C (67°F), with highs reaching up to 34°C (93°F) and lows dropping to around 2°C (36°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 precipitation amount is 130 mm (5.1 in) over the course of 9 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 130 mm (5.1 inches) of precipitation spread over approximately 9 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 78%. With an average temperature of 19°C (67°F), this humidity feels like a warm, heavy blanket enveloping you, making traveling feel both sticky and sluggish as you navigate through the day.

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 78%, 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 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 8, which falls under the very 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	-6°C (21°F)	47 mm (1.9 inches)	81%	moderate
February Weather	-5°C (23°F)	58 mm (2.3 inches)	81%	moderate
March Weather	3°C (38°F)	73 mm (2.9 inches)	81%	high
April Weather	9°C (48°F)	81 mm (3.2 inches)	82%	very high
May Weather	16°C (62°F)	150 mm (5.9 inches)	78%	very high
June Weather	23°C (73°F)	125 mm (4.9 inches)	81%	extreme
July Weather	24°C (76°F)	81 mm (3.2 inches)	79%	very high
August Weather	22°C (73°F)	83 mm (3.3 inches)	77%	very high
September Weather	19°C (67°F)	130 mm (5.1 inches)	78%	very high
October Weather	11°C (53°F)	136 mm (5.4 inches)	78%	high
November Weather	3°C (38°F)	48 mm (1.9 inches)	87%	moderate
December Weather	-1°C (30°F)	45 mm (1.8 inches)	84%	moderate