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September Weather in Porsgrunn, Norway

Last updated: August 27, 2025

In September, the average temperature in Porsgrunn, Norway hovers around 12°C (54°F). Expect a cool minimum of 1°C (35°F) and a pleasant maximum of 24°C (76°F). However, be prepared for some rain, as precipitation totals around 126 mm (5.0 in) over the course of 13 days. With an average humidity level of 86%, you'll definitely feel the dampness in the air.

September Temperature in Porsgrunn

In September in Porsgrunn, the average temperature is 12°C (54°F). Maximums can reach 24°C (76°F), while minimums can drop to as low as 1°C (35°F). This variability in temperature makes it advisable to pack layers for your travels.

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

The chart illustrates September temperature patterns in Porsgrunn, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Porsgrunn, September typically has an average temperature of 12°C (54°F), with highs reaching up to 24°C (76°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec303034415160636054453731
Data source: Temperature data for Porsgrunn generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Porsgrunn

In Porsgrunn in September, the precipitation amount is 126 mm (5.0 in) over the course of 13 days.

September Precipitation Trends in Porsgrunn

The chart displays monthly precipitation patterns in Porsgrunn, 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 Porsgrunn, September typically receives around 126 mm (5.0 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec76797939869410494126137116130
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Porsgrunn

In Porsgrunn in September, humidity is 86%. With an average temperature of 12°C (54°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities uncomfortable and travel challenging due to the heavy, muggy atmosphere.

September Average Humidity in Porsgrunn

This chart illustrates the average monthly humidity levels in Porsgrunn, 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 Porsgrunn is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec93%91%88%83%75%74%74%78%86%92%92%92%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Porsgrunn

In Porsgrunn in September, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Porsgrunn for better planning.

Maximum UV Index Levels in Porsgrunn for September

The chart shows the monthly maximum UV Index (UVI) for Porsgrunn 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 Porsgrunn typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec113457754211
Data source: Porsgrunn 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 Porsgrunn Compares to Other Months

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

This table compares monthly weather conditions in Porsgrunn, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)76 mm (3.0 inches)93%low
February Weather-1°C (30°F)79 mm (3.1 inches)91%low
March Weather1°C (35°F)79 mm (3.1 inches)88%moderate
April Weather5°C (42°F)39 mm (1.5 inches)83%moderate
May Weather10°C (51°F)86 mm (3.4 inches)75%moderate
June Weather16°C (60°F)94 mm (3.7 inches)74%high
July Weather17°C (63°F)104 mm (4.1 inches)74%high
August Weather16°C (60°F)94 mm (3.7 inches)78%moderate
September Weather12°C (54°F)126 mm (5.0 inches)86%moderate
October Weather7°C (46°F)137 mm (5.4 inches)92%low
November Weather3°C (38°F)116 mm (4.6 inches)92%low
December Weather-1°C (31°F)130 mm (5.1 inches)92%low

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