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September Weather in South Plainfield, United States

Last updated: June 24, 2025

In September, the average temperature in South Plainfield, United States hovers around 21°C (70°F), making for a pleasant atmosphere. Expect minimum temperatures to dip to 6°C (44°F) and maximums soaring up to 35°C (96°F). With an average humidity of 68%, the weather feels moderately comfortable. However, be prepared for some rain, as 89 mm (3.5 in) of precipitation may fall over the course of 9 days.

September Temperature in South Plainfield

In September in South Plainfield, the average temperature is 21°C (70°F). Maximum temperatures can reach 35°C (96°F), while minimum temperatures can dip as low as 6°C (44°F). This weather makes it an ideal time for traveling, allowing for comfortable outdoor adventures and exploration.

September Weather in South Plainfield: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in South Plainfield, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South Plainfield, September typically has an average temperature of 21°C (70°F), with highs reaching up to 35°C (96°F) and lows dropping to around 6°C (44°F).
JanFebMarAprMayJunJulAugSepOctNovDec343743536372787670604638
Data source: Temperature data for South Plainfield 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 South Plainfield

In South Plainfield in September, the precipitation amount is 89 mm (3.5 in) during a span of 9 days.

September Precipitation Trends in South Plainfield

The chart displays monthly precipitation patterns in South Plainfield, 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 South Plainfield, September typically receives around 89 mm (3.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec651071071101291021401338913682106
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in South Plainfield

In South Plainfield in September humidity is 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

September Average Humidity in South Plainfield

This chart illustrates the average monthly humidity levels in South Plainfield, 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 South Plainfield is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in South Plainfield

In South Plainfield 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 South Plainfield.

Maximum UV Index Levels in South Plainfield for September

The chart shows the monthly maximum UV Index (UVI) for South Plainfield 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 South Plainfield typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
Data source: South Plainfield 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 South Plainfield Compares to Other Months

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

This table compares monthly weather conditions in South Plainfield, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)65 mm (2.6 inches)84%moderate
February Weather3°C (37°F)107 mm (4.2 inches)82%moderate
March Weather6°C (43°F)107 mm (4.2 inches)81%high
April Weather11°C (53°F)110 mm (4.3 inches)78%very high
May Weather17°C (63°F)129 mm (5.1 inches)69%very high
June Weather22°C (72°F)102 mm (4.0 inches)69%very high
July Weather25°C (78°F)140 mm (5.5 inches)62%very high
August Weather24°C (76°F)133 mm (5.2 inches)65%very high
September Weather21°C (70°F)89 mm (3.5 inches)68%very high
October Weather16°C (60°F)136 mm (5.4 inches)74%high
November Weather8°C (46°F)82 mm (3.2 inches)82%moderate
December Weather3°C (38°F)106 mm (4.2 inches)80%low

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