Climate averages 1991–2020
San Tan Valley weather
in September.
A very hot, fairly dry month: the 4th warmest and the 7th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a very hot month in San Tan Valley: daytime highs average 35.9°C and nights cool to about 22.7°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 26 mm of rain on roughly 3 days, which makes September a fairly dry month (the 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 24 min on an average September day.
The nearest other city in this atlas is Chandler (32 km away). In September its highs average 37.0°C, 1.1°C warmer than San Tan Valley, with 25 mm of rain.
Among the 498 cities listed in the United States, San Tan Valley ranks 13th of 498 for the warmest September highs and joint 134th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; San Tan Valley is 9.0°C warmer than that mean.
From September to October, average highs fall by 5.9°C to 30.0°C, and monthly rainfall falls from 26 mm to 18 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Tan Valley climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 18.2°C4.9°C | 4.9°C | 38 | 4.2 | 10.210 h |
| February | 19.8°C6.3°C | 6.3°C | 41 | 4.4 | 11.011 h |
| March | 23.8°C8.9°C | 8.9°C | 27 | 3.0 | 12.012 h |
| April | 28.2°C12.5°C | 12.5°C | 8.4 | 1.4 | 13.013 h |
| May | 33.2°C17.4°C | 17.4°C | 4.1 | 0.7 | 13.914 h |
| June | 38.7°C22.6°C | 22.6°C | 2.0 | 0.6 | 14.314 h |
| July | 39.3°C26.5°C | 26.5°C | 21 | 3.7 | 14.114 h |
| August | 38.4°C26.2°C | 26.2°C | 27 | 4.9 | 13.413 h |
| September, selected | 35.9°C22.7°C | 22.7°C | 26 | 3.2 | 12.412 h |
| October | 30.0°C15.9°C | 15.9°C | 18 | 2.4 | 11.411 h |
| November | 23.3°C9.6°C | 9.6°C | 19 | 2.4 | 10.510 h |
| December | 17.6°C4.8°C | 4.8°C | 34 | 4.3 | 10.010 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Chandler in SeptemberUnited States · 32 kmHigh 37.0°C · Low 23.1°C · 25 mm rain
- Mesa in SeptemberUnited States · 38 kmHigh 36.6°C · Low 22.8°C · 26 mm rain
- Tempe in SeptemberUnited States · 43 kmHigh 36.8°C · Low 23.2°C · 24 mm rain
- Scottsdale in SeptemberUnited States · 49 kmHigh 36.5°C · Low 23.1°C · 24 mm rain
- Phoenix in SeptemberUnited States · 58 kmHigh 36.9°C · Low 23.4°C · 24 mm rain
- Glendale (Arizona), United States in SeptemberUnited States · 72 kmHigh 36.8°C · Low 23.5°C · 22 mm rain
- Peoria (Arizona), United States in SeptemberUnited States · 79 kmHigh 36.6°C · Low 23.4°C · 22 mm rain
- Avondale in SeptemberUnited States · 81 kmHigh 37.4°C · Low 23.9°C · 22 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Tan Valley) is explained once on the San Tan Valley year overview and on the Sources, method and limits page.