September Weather in Portal, United States

Last updated: June 24, 2025

In September, the average temperature in Portal, United States reaches a warm 26°C (79°F). However, temperatures can vary significantly, with a minimum of 13°C (56°F) and a scorching maximum of 38°C (101°F). Expect 87 mm (3.4 in) of precipitation spread over 10 days, contributing to an average humidity of 83%. Prepare for a tropical climate that combines warmth with occasional rain!

September Temperature in Portal

In September in Portal, the average temperature is 26°C (79°F). Maximums can reach 38°C (101°F), while minimums can drop to as low as 13°C (56°F). This makes Portal a great travel destination for those who enjoy warm weather with a cool reprieve during the night.

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

The chart illustrates September temperature patterns in Portal, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portal, September typically has an average temperature of 26°C (79°F), with highs reaching up to 38°C (101°F) and lows dropping to around 13°C (56°F).

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

September Precipitation in Portal

In Portal in September, the precipitation amount is 87 mm (3.4 in) over the course of 10 days.

September Precipitation Trends in Portal

The chart displays monthly precipitation patterns in Portal, 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 Portal, September typically receives around 87 mm (3.4 inches) of precipitation spread over approximately 10 days.

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

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Millimeters (mm) Inches (in)

September Humidity in Portal

In Portal in September, humidity is 83%. With an average temperature of 26°C (79°F), this humidity feels like a heavy blanket enveloping you, making travel an exercise in endurance as the air clings to your skin and saps your energy.

September Average Humidity in Portal

This chart illustrates the average monthly humidity levels in Portal, 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 Portal is approximately 83%, 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 Portal

In Portal in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Portal.

Maximum UV Index Levels in Portal for September

The chart shows the monthly maximum UV Index (UVI) for Portal 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 Portal typically reaches 10, which falls under the very high exposure category.

Data source: Portal 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 Portal Compares to Other Months

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

This table compares monthly weather conditions in Portal, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	11°C (51°F)	81 mm (3.2 inches)	86%	moderate
February Weather	14°C (57°F)	97 mm (3.8 inches)	81%	high
March Weather	16°C (61°F)	68 mm (2.7 inches)	81%	very high
April Weather	19°C (67°F)	92 mm (3.6 inches)	79%	very high
May Weather	24°C (76°F)	78 mm (3.1 inches)	75%	extreme
June Weather	27°C (80°F)	112 mm (4.4 inches)	75%	extreme
July Weather	28°C (83°F)	127 mm (5.0 inches)	80%	extreme
August Weather	28°C (82°F)	119 mm (4.7 inches)	81%	extreme
September Weather	26°C (79°F)	87 mm (3.4 inches)	83%	very high
October Weather	22°C (72°F)	76 mm (3.0 inches)	78%	very high
November Weather	14°C (58°F)	61 mm (2.4 inches)	85%	high
December Weather	12°C (54°F)	121 mm (4.8 inches)	87%	moderate