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August Weather in Phoenix, United States

Last updated: June 24, 2025

In August, the average temperature in Phoenix, United States hovers around 20°C (69°F). Be prepared for a range, as lows can dip to 7°C (45°F), while highs may soar to 37°C (99°F). Expect light rainfall, with an average precipitation amount of 9 mm (0.4 in) spread over 2 days. The average humidity during this month is around 67%, creating a pleasantly warm atmosphere.

August Temperature in Phoenix

In August in Phoenix, the average temperature is 20°C (69°F). Maximums can reach 37°C (99°F), and minimums can be as low as 7°C (45°F). This range makes it a great time for travelers to enjoy a mix of warm and cooler days, perfect for various outdoor activities.

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

The chart illustrates August 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, August typically has an average temperature of 20°C (69°F), with highs reaching up to 37°C (99°F) and lows dropping to around 7°C (45°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.

August Precipitation in Phoenix

In Phoenix in August, the precipitation amount is 9 mm (0.4 in) over the course of 2 days.

August Precipitation Trends in Phoenix

The chart displays monthly precipitation patterns in Phoenix, with values for each month alongside August’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August’s conditions compare to those of other months. In Phoenix, August typically receives around 9 mm (0.4 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec12613611996673249445194106
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Phoenix

In Phoenix in August, humidity is 67%. With an average temperature of 20°C (69°F), this humidity feels like a warm, gentle embrace that clings to your skin, creating a comfortable yet slightly sticky atmosphere that can be refreshing while exploring the sights, provided you stay hydrated and take breaks in the shade.

August Average Humidity in Phoenix

This chart illustrates the average monthly humidity levels in Phoenix, with August’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In August, average humidity in Phoenix is approximately 67%, 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 August generated using information from the Copernicus Climate Change Service.

August UV Index in Phoenix

In Phoenix in August, 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 Phoenix.

Maximum UV Index Levels in Phoenix for August

The chart shows the monthly maximum UV Index (UVI) for Phoenix in August, 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 August, the maximum UV index in Phoenix typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3478111110108642
Data source: Phoenix August 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 August 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 August’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 August’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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