September Weather in Port Saint John, United States

Last updated: June 24, 2025

The average temperature in Port Saint John, United States during September is a warm 27°C (81°F). Expect lows of 23°C (74°F) and highs reaching up to 33°C (91°F). Prepare for 189 mm (7.4 in) of precipitation spread across 21 days, contributing to a notable average humidity of 83%. Enjoy the warmth, but don't forget your umbrella!

September Temperature in Port Saint John

In September in Port Saint John, the average temperature is 27°C (81°F), with maximums reaching 33°C (91°F) and minimums dropping to 23°C (74°F). This mild climate makes it a perfect time for outdoor adventures and exploration.

September Weather in Port Saint John: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Port Saint John, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Port Saint John, September typically has an average temperature of 27°C (81°F), with highs reaching up to 33°C (91°F) and lows dropping to around 23°C (74°F).

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

September Precipitation in Port Saint John

In Port Saint John in September, the total precipitation amount is 189 mm (7.4 in), spread over a period of 21 days.

September Precipitation Trends in Port Saint John

The chart displays monthly precipitation patterns in Port Saint John, 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 Port Saint John, September typically receives around 189 mm (7.4 inches) of precipitation spread over approximately 21 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 Port Saint John

In Port Saint John in September humidity is 83%. With an average temperature of 27°C (81°F), this humidity feels like a warm blanket enveloping you, making sightseeing and outdoor activities feel more exhausting and requiring frequent breaks to relax in the shade or cool off.

September Average Humidity in Port Saint John

This chart illustrates the average monthly humidity levels in Port Saint John, 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 Port Saint John 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 Port Saint John

In Port Saint John in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Port Saint John.

Maximum UV Index Levels in Port Saint John for September

The chart shows the monthly maximum UV Index (UVI) for Port Saint John 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 Port Saint John typically reaches 11, which falls under the extreme exposure category.

Data source: Port Saint John 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 Port Saint John Compares to Other Months

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

This table compares monthly weather conditions in Port Saint John, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	17°C (64°F)	38 mm (1.5 inches)	83%	high
February Weather	19°C (67°F)	51 mm (2.0 inches)	80%	very high
March Weather	20°C (69°F)	25 mm (1.0 inches)	75%	very high
April Weather	23°C (73°F)	72 mm (2.8 inches)	70%	extreme
May Weather	25°C (77°F)	124 mm (4.9 inches)	68%	extreme
June Weather	26°C (80°F)	164 mm (6.4 inches)	75%	extreme
July Weather	27°C (82°F)	172 mm (6.8 inches)	79%	extreme
August Weather	28°C (82°F)	220 mm (8.7 inches)	81%	extreme
September Weather	27°C (81°F)	189 mm (7.4 inches)	83%	extreme
October Weather	26°C (78°F)	107 mm (4.2 inches)	81%	very high
November Weather	22°C (71°F)	62 mm (2.4 inches)	82%	high
December Weather	19°C (66°F)	65 mm (2.6 inches)	84%	moderate