Phoenix, Arizona weather in September

Averages from 2021–2025 (150 days of record).

Average high: 100°F
Average low: 77°F
Rainy days: ~4 per month
Total precipitation: 1.5 in
Warmest recorded: 114°F
Coldest recorded: 66°F

Expect September days in Phoenix, Arizona to top out around 100°F and cool to about 77°F overnight, with roughly 4 days of measurable rain across the month. In recent years September has ranged from 66°F to 114°F.

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Current Phoenix, Arizona forecast → · Historical data by Open-Meteo (ERA5).