September is one of the cooler months of the year in Scottsdale, with average highs near 12.5°C and lows around 7.1°C (mean 9.8°C). It is about average for rainfall, averaging 79 mm of rainfall and 84% relative humidity across the period.
September is one of the cooler months of the year in Scottsdale. Across 45 years of records, the warmest September in Scottsdale was 2023 — when the month averaged 11.1°C — while the coldest was 1994 at 8.3°C. Typical September days reach 12.5°C with nights near 7.1°C. The long-term trend is warming, about 0.2°C per decade.
September is about average for rainfall in Scottsdale, averaging 79 mm of rainfall. The wettest September on record was 1996 with 151 mm, while the driest was 2015 at 24 mm.
Relative humidity in Scottsdale during September averages 84%. The most humid September was 2016 at 87%, and the least humid were 1994 and 2008 at 81%.
September receives about 3.8 kWh/m²/day of solar energy in Scottsdale. The sunniest Septembers were 1987, 2019 and 2023 at 4.2 kWh/m²/day, and the cloudiest was 2009 at 3.3.
Average wind speed in Scottsdale during September is 3.9 m/s. The windiest September was 2002 at 5.3 m/s, while the calmest was 2015 at 2.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.7°C | 9.3°C | 10.0°C | 9.9°C | 10.2°C | +0.5°C |
| Avg High | 12.5°C | 12.0°C | 12.6°C | 12.7°C | 12.9°C | +0.4°C |
| Avg Low | 7.0°C | 6.6°C | 7.4°C | 7.1°C | 7.6°C | +0.6°C |
| Avg Rain | 77 mm | 81 mm | 93 mm | 71 mm | 69 mm | -7 mm |
September temperatures in Scottsdale have risen by about 0.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 1.7°C (1994) to a record high of 18.7°C (2023).
Rainfall in September is about average for rainfall, averaging 79 mm, with a wettest year of 151 mm.
A quieter season to visit Scottsdale
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Scottsdale. That said, September — with days averaging 12.5°C and nights around 7.1°C (mean 9.8°C) and moderate rainfall (79 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 12.6°C | 10.1°C | 7.5°C | 15.1°C | 4.3°C | 82 mm | 81% | 4.9 m/s | 3.8 |
| 2024 | 12.6°C | 10.1°C | 7.6°C | 14.4°C | 3.7°C | 95 mm | 83% | 5.1 m/s | 3.6 |
| 2023 🔥 | 14.0°C | 11.1°C | 8.2°C | 18.7°C | 5.4°C | 33 mm | 82% | 3.8 m/s | 4.2 |
| 2022 | 12.9°C | 10.2°C | 7.6°C | 17.1°C | 2.9°C | 67 mm | 85% | 3.1 m/s | 3.6 |
| 2021 | 12.5°C | 9.6°C | 6.8°C | 15.9°C | 3.7°C | 78 mm | 82% | 4.3 m/s | 4 |
| 2020 | 12.5°C | 10.0°C | 7.6°C | 16.4°C | 4.2°C | 62 mm | 86% | 3.8 m/s | 3.7 |
| 2019 | 12.6°C | 9.6°C | 6.6°C | 17.4°C | 3.2°C | 65 mm | 83% | 3.7 m/s | 4.2 |
| 2018 | 12.4°C | 9.6°C | 6.9°C | 14.4°C | 3.3°C | 42 mm | 82% | 3.9 m/s | 4.1 |
| 2017 | 11.7°C | 9.1°C | 6.4°C | 16.5°C | 3.9°C | 68 mm | 83% | 4.6 m/s | 3.8 |
| 2016 | 13.1°C | 10.6°C | 8.0°C | 15.7°C | 5.7°C | 96 mm | 87% | 3.1 m/s | 3.5 |
| 2015 | 13.1°C | 10.0°C | 6.9°C | 16.9°C | 2.6°C | 24 mm | 84% | 2.7 m/s | 4.1 |
| 2014 | 13.6°C | 10.6°C | 7.6°C | 16.9°C | 4.2°C | 53 mm | 84% | 3.5 m/s | 4.1 |
| 2013 | 12.8°C | 10.4°C | 8.0°C | 15.9°C | 3.6°C | 107 mm | 87% | 4.1 m/s | 3.6 |
| 2012 | 12.4°C | 10.0°C | 7.5°C | 15.6°C | 4.0°C | 106 mm | 86% | 4.2 m/s | 3.6 |
| 2011 | 12.9°C | 10.0°C | 7.0°C | 16.8°C | 3.0°C | 65 mm | 83% | 3.7 m/s | 4 |
| 2010 | 12.0°C | 9.2°C | 6.3°C | 15.2°C | 3.2°C | 86 mm | 82% | 4.7 m/s | 3.9 |
| 2009 | 12.7°C | 10.2°C | 7.8°C | 15.1°C | 5.8°C | 125 mm | 85% | 4 m/s | 3.3 |
| 2008 | 12.5°C | 9.7°C | 6.9°C | 15.3°C | 3.2°C | 76 mm | 81% | 4.3 m/s | 3.6 |
| 2007 | 12.9°C | 10.1°C | 7.3°C | 15.5°C | 3.6°C | 71 mm | 83% | 3.9 m/s | 3.6 |
| 2006 | 12.9°C | 10.1°C | 7.3°C | 16.3°C | 4.4°C | 68 mm | 82% | 3.9 m/s | 4 |
| 2005 | 13.0°C | 10.4°C | 7.7°C | 16.6°C | 4.2°C | 148 mm | 86% | 3.1 m/s | 3.5 |
| 2004 | 12.9°C | 10.3°C | 7.6°C | 15.8°C | 3.0°C | 46 mm | 85% | 3.7 m/s | 3.9 |
| 2003 | 11.3°C | 8.6°C | 6.0°C | 13.6°C | 2.9°C | 96 mm | 81% | 5.2 m/s | 3.9 |
| 2002 | 12.3°C | 9.7°C | 7.1°C | 16.1°C | 4.5°C | 111 mm | 82% | 5.3 m/s | 3.7 |
| 2001 | 13.6°C | 11.0°C | 8.4°C | 17.4°C | 5.4°C | 68 mm | 85% | 3.4 m/s | 3.8 |
| 2000 | 12.1°C | 9.9°C | 7.7°C | 14.9°C | 5.5°C | 123 mm | 85% | 5.1 m/s | 3.5 |
| 1999 | 13.4°C | 10.6°C | 7.8°C | 17.5°C | 4.2°C | 40 mm | 85% | 3 m/s | 3.7 |
| 1998 | 12.9°C | 10.5°C | 8.0°C | 15.3°C | 4.8°C | 113 mm | 85% | 4 m/s | 3.7 |
| 1997 | 12.4°C | 9.7°C | 6.9°C | 14.3°C | 3.6°C | 119 mm | 84% | 3.1 m/s | 3.8 |
| 1996 🌧️ | 11.1°C | 8.6°C | 6.2°C | 14.0°C | 3.5°C | 151 mm | 84% | 4.5 m/s | 3.5 |
| 1995 | 11.4°C | 8.7°C | 6.0°C | 14.3°C | 2.4°C | 44 mm | 83% | 3.7 m/s | 3.7 |
| 1994 ❄️ | 11.2°C | 8.3°C | 5.5°C | 15.4°C | 1.7°C | 34 mm | 81% | 4.4 m/s | 4 |
| 1993 | 12.6°C | 9.7°C | 6.9°C | 17.3°C | 2.9°C | 68 mm | 84% | 3.1 m/s | 3.8 |
| 1992 | 11.1°C | 8.6°C | 6.1°C | 13.7°C | 3.0°C | 94 mm | 83% | 3.5 m/s | 3.7 |
| 1991 | 11.7°C | 8.9°C | 6.2°C | 13.8°C | 3.3°C | 91 mm | 85% | 3.7 m/s | 3.9 |
| 1990 | 12.3°C | 9.5°C | 6.6°C | 14.9°C | 3.4°C | 59 mm | 84% | 3.2 m/s | 3.7 |
| 1989 | 12.7°C | 9.8°C | 6.9°C | 15.7°C | 4.3°C | 71 mm | 85% | 3.2 m/s | 3.8 |
| 1988 | 13.2°C | 10.7°C | 8.2°C | 15.4°C | 3.6°C | 101 mm | 86% | 4 m/s | 3.5 |
| 1987 | 12.9°C | 9.9°C | 6.9°C | 17.5°C | 3.1°C | 44 mm | 84% | 3.9 m/s | 4.2 |
| 1986 | 11.8°C | 9.2°C | 6.6°C | 14.7°C | 3.3°C | 84 mm | 85% | 3.8 m/s | 3.6 |
| 1985 | 12.7°C | 9.6°C | 6.5°C | 15.6°C | 3.8°C | 31 mm | 84% | 3.1 m/s | 4.1 |
| 1984 | 11.9°C | 9.3°C | 6.7°C | 13.9°C | 3.2°C | 148 mm | 86% | 3.5 m/s | 3.7 |
| 1983 | 11.7°C | 9.3°C | 7.0°C | 13.9°C | 3.4°C | 111 mm | 84% | 4.5 m/s | — |
| 1982 | 12.4°C | 9.4°C | 6.5°C | 16.0°C | 2.6°C | 61 mm | 82% | 3.8 m/s | — |
| 1981 | 12.8°C | 10.2°C | 7.7°C | 15.0°C | 3.7°C | 38 mm | 86% | 4.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 12.5°C with lows near 7.1°C (mean 9.8°C), based on 45 years of NASA POWER data.
September averages 79 mm of rainfall in Scottsdale, about average for rainfall. The wettest on record was 151 mm in 1996.
The hottest September reached 18.7°C in 2023. The coldest dipped to 1.7°C in 1994.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.6°C. Daytime highs moved from 12.3°C to 12.9°C and overnight lows from 6.9°C to 7.5°C over the same span.
September is one of the cooler months of the year in Scottsdale and about average for rainfall, so plan for around 12.5°C daytime highs and 7.1°C at night.
Not quite — September is the 4th coolest month in Scottsdale, averaging 9.8°C.
For September in Scottsdale, pack warm layers and a jacket for chilly mornings, with typical highs of 12.5°C and lows of 7.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 84% — quite humid.
Average wind speed in September is 3.9 m/s. The windiest September on record averaged 5.3 m/s (2002).
The wettest September on record was 1996 with 151 mm. On average, September sees 79 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Scottsdale behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
