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September Weather in Duncan, United States

Last updated: June 24, 2025

In September, the average temperature in Duncan, United States is a warm 25°C (77°F), but you can expect fluctuations from a cool 8°C (47°F) to a scorching 38°C (101°F). With an average humidity of 64%, the atmosphere can feel quite muggy. Be prepared for some rain, as 88 mm (3.5 in) of precipitation is expected over 6 days this month.

September Temperature in Duncan

In September in Duncan, the average temperature is 25°C (77°F). The maximum can reach 38°C (101°F), and the minimum can be as low as 8°C (47°F). This diverse range of temperatures makes Duncan an ideal destination for travelers seeking both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Duncan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Duncan, September typically has an average temperature of 25°C (77°F), with highs reaching up to 38°C (101°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec414356617280858377645246
Data source: Temperature data for Duncan 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 Duncan

In Duncan in September, the precipitation amount is 88 mm (3.5 in) over the course of 6 days.

September Precipitation Trends in Duncan

The chart displays monthly precipitation patterns in Duncan, 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 Duncan, September typically receives around 88 mm (3.5 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec4754959513563335888972741
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Duncan

In Duncan in September, humidity is 64%. With an average temperature of 25°C (77°F), this humidity feels like a warm embrace, making outdoor excursions feel a bit heavier, yet still inviting for travelers seeking a vibrant atmosphere.

September Average Humidity in Duncan

This chart illustrates the average monthly humidity levels in Duncan, 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 Duncan is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%76%70%72%82%82%80%72%64%71%81%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Duncan

In Duncan 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 Duncan.

Maximum UV Index Levels in Duncan for September

The chart shows the monthly maximum UV Index (UVI) for Duncan 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 Duncan typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111110854
Data source: Duncan 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 Duncan Compares to Other Months

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

This table compares monthly weather conditions in Duncan, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (42°F)47 mm (1.9 inches)76%moderate
February Weather6°C (43°F)54 mm (2.1 inches)76%high
March Weather13°C (56°F)95 mm (3.8 inches)70%very high
April Weather16°C (62°F)95 mm (3.7 inches)72%very high
May Weather22°C (72°F)135 mm (5.3 inches)82%extreme
June Weather27°C (80°F)63 mm (2.5 inches)82%extreme
July Weather29°C (85°F)33 mm (1.3 inches)80%extreme
August Weather29°C (84°F)58 mm (2.3 inches)72%extreme
September Weather25°C (77°F)88 mm (3.5 inches)64%very high
October Weather18°C (64°F)97 mm (3.8 inches)71%very high
November Weather11°C (52°F)27 mm (1.1 inches)81%moderate
December Weather8°C (46°F)41 mm (1.6 inches)84%moderate

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