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September Weather in Phoenix, United States

Last updated: June 24, 2025

In Phoenix, United States, the average temperature in September hovers around 16°C (61°F), creating a mild climate. Expect lows around 0°C (33°F) and highs reaching up to 35°C (95°F). This period sees an average precipitation of 44 mm (1.7 in) over approximately 5 days, complemented by an average humidity level of 66%.

September Temperature in Phoenix

In September in Phoenix, the average temperature is 16°C (61°F). Maximums can reach 35°C (95°F), while minimums can dip down to 0°C (33°F). Be prepared for a wide range of temperatures and pack accordingly for your trip!

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

The chart illustrates September temperature patterns in Phoenix, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Phoenix, September typically has an average temperature of 16°C (61°F), with highs reaching up to 35°C (95°F) and lows dropping to around 0°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec383742475462696961504237
Data source: Temperature data for Phoenix 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 Phoenix

In Phoenix in September, the precipitation amount is 44 mm (1.7 in) over the course of 5 days.

September Precipitation Trends in Phoenix

The chart displays monthly precipitation patterns in Phoenix, 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 Phoenix, September typically receives around 44 mm (1.7 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec12613611996673249445194106
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Phoenix

In Phoenix in September humidity is 66%. With an average temperature of 16°C (61°F), this humidity feels like a heavy blanket enveloping you, making travel somewhat uncomfortable as the air grows sticky and tedious, slightly sapping your energy as you explore.

September Average Humidity in Phoenix

This chart illustrates the average monthly humidity levels in Phoenix, 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 Phoenix is approximately 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%85%86%83%83%83%78%67%66%77%87%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Phoenix

In Phoenix 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 Phoenix.

Maximum UV Index Levels in Phoenix for September

The chart shows the monthly maximum UV Index (UVI) for Phoenix 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 Phoenix typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3478111110108642
Data source: Phoenix 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 Phoenix Compares to Other Months

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

This table compares monthly weather conditions in Phoenix, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)125 mm (4.9 inches)84%moderate
February Weather3°C (38°F)136 mm (5.4 inches)85%moderate
March Weather5°C (42°F)119 mm (4.7 inches)86%high
April Weather8°C (47°F)96 mm (3.8 inches)83%very high
May Weather12°C (54°F)67 mm (2.6 inches)83%extreme
June Weather17°C (62°F)32 mm (1.3 inches)83%extreme
July Weather21°C (70°F)4 mm (0.2 inches)78%very high
August Weather20°C (69°F)9 mm (0.4 inches)67%very high
September Weather16°C (61°F)44 mm (1.7 inches)66%very high
October Weather10°C (51°F)51 mm (2.0 inches)77%high
November Weather6°C (43°F)94 mm (3.7 inches)87%moderate
December Weather3°C (37°F)106 mm (4.2 inches)87%low

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