September weather forecast
Arizona, USA

September in Arizona heralds the beginning of a shift from the stifling summer heat towards the more temperate conditions of autumn. The month is marked by a steady decline in temperatures, making it progressively more comfortable, especially in the latter half.

The southern desert expanses, such as Phoenix, start to experience some relief from the relentless summer heat. Daytime temperatures in this region typically fluctuate from 90°F (32.2°C) to 100°F (37.8°C). Nights provide a more noticeable respite, with temperatures comfortably settling between 70°F (21.1°C) and 80°F (26.7°C). Monsoonal activities from the preceding months begin to wane, but occasional rain showers can still occur, especially in the early part of September.

In contrast, the northern highland areas like Flagstaff already start feeling the autumn chill. Day temperatures here generally vary from 70°F (21.1°C) to 80°F (26.7°C). Nights, however, can be crisp, with temperatures ranging from 45°F (7.2°C) to 55°F (12.8°C). Rainfall becomes sporadic, and the landscape starts to show hints of the upcoming fall colors.

Compared to the peak heat and monsoonal patterns of August, September is relatively calm and transitional. The month’s progression sees a continuous reduction in temperatures, paving the way for the more consistent autumnal weather of October in Arizona.

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• Phoenix - September »
  On the first day of September sunrise is at 6:02 am and sunset at 6:53 pm. In Phoenix in September, it is raining for 4.7 days, with typically 0.67" (17mm) of accumulated precipitation.
• Tucson - September »
  September in Tucson marks the ornate transition from summer to fall, resulting in a noticeable decrease in humidity. In Tucson, in September, it is raining for 8.6 days, with typically 0.98" (25mm) of accumulated precipitation.
• Mesa - September »
  In Mesa, during September, the rain falls for 7.4 days and regularly aggregates up to 0.79" (20mm) of precipitation. September ushers in a minor alteration in Mesa's climate, with the average high-temperature moving from August's very hot 100.9°F (38.3°C) to a still fiery hot 95.4°F (35.2°C).
• Chandler - September »
  In Chandler, during September, the rain falls for 7.7 days and regularly aggregates up to 0.98" (25mm) of precipitation. In Chandler, during September, the rain falls for 7.7 days and regularly aggregates up to 0.98" (25mm) of precipitation.
• Scottsdale - September »
  In Scottsdale, during September, the rain falls for 7.3 days and regularly aggregates up to 0.94" (24mm) of precipitation. On the first day of September in Scottsdale, sunrise is at 6:02 am and sunset at 6:52 pm.
• Glendale - September »
  In Glendale, during September, the rain falls for 6.7 days and regularly aggregates up to 1.1" (28mm) of precipitation. On the first day of September in Glendale, sunrise is at 6:03 am and sunset at 6:53 pm.
• Gilbert - September »
  Start of September in Gilbert brings a slight shift in the average high-temperature, dipping a bit from August's fiery hot 100.9°F (38.3°C) to a still sweltering 95.4°F (35.2°C). In Gilbert, in September, it is raining for 7.4 days, with typically 0.79" (20mm) of accumulated precipitation.
• Tempe - September »
  In Tempe, during September, the rain falls for 7.3 days and regularly aggregates up to 0.94" (24mm) of precipitation. On the first day of September in Tempe, sunrise is at 6:02 am and sunset at 6:52 pm.
• Peoria - September »
  In Peoria, Arizona, in September, it is raining for 6.7 days, with typically 1.1" (28mm) of accumulated precipitation. In Peoria, during September, the rain falls for 6.7 days and regularly aggregates up to 1.1" (28mm) of precipitation.
• Surprise - September »
  On the first day of September in Surprise, sunrise is at 6:03 am and sunset at 6:54 pm. In Surprise, during September, the rain falls for 7.1 days and regularly aggregates up to 1.18" (30mm) of precipitation.
• Yuma - September »
  September in Yuma, Arizona, implies a soft temperature shift, with average high-temperatures reducing from August's extremely hot 105.1°F (40.6°C) to a fiery hot 99.5°F (37.5°C). The months with the highest UV index in Yuma, Arizona, are June through September, with an average maximum UV index of 8.