San Tan Valley, AZ weather in September
In September, San Tan Valley sees highs around 101°F and lows around 70°F: very hot and mostly dry. There are about 3 days with rain. Plan outdoor time for mornings and evenings.
- Normal high
- 101°F
- Normal low
- 70°F
- Wet days
- 3
- 0.7 in total
- Muggy days
- 2
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 104°F | 96°F |
| Normal low | 74°F | 64°F |
| Chance of a wet day | 15% | 8% |
| Sunrise / sunset | 6:00 am / 6:51 pm | 6:19 am / 6:12 pm |
| Daylight | 12.8 h | 11.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Arizona time (no daylight saving)).
A typical September day
- 6 am79°Fdew point 54°F
- 9 am85°Fdew point 53°F
- Noon94°Fdew point 52°F
- 3 pm98°Fdew point 49°F
- 6 pm97°Fdew point 48°F
- 9 pm90°Fdew point 50°F
NOAA hourly normals (local standard time) from Phoenix Sky Harbor Intl Airport (32 mi away); average wind 6 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F0 of 30
- Hot dayshigh 90°F or more29 of 30
- Muggy daysdaily mean dew point 65°F or more2 of 30
- Wet daysat least 0.01 in of rain or melted snow3 of 30
- Notable rainat least 0.10 in2 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 0.7 in; a dry September brings about 0.2 in and a wet one about 0.8 in (25th and 75th percentiles). Days with half an inch or more are rare.
How September varies from year to year
- Warmest September, 1991-20201995: average high 105°F
- Coolest September2006: average high 96°F
- Wettest September1999: 2.9 in
- Driest September2001: no measurable precipitation
- Highest reading115°F (September 1, 1995)
- Lowest reading37°F (September 20, 1993)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 105°F | 101°F | 91°F |
| Normal low | 77°F | 70°F | 56°F |
| Wet days | 5 | 3 | 2 |
| Comfortable days | 0 | 0 | 3 |
| Daylight | 13.3 h | 12.4 h | 11.3 h |
Highs change by -4°F from August and -10°F into October.
Nearby alternatives in September
- Cooler: Tucson, AZ76 mi · high 95°F · 4 wet days
How San Tan Valley ranks in September
- Normal high4th warmest of 378 cities; 2nd of 13 in Arizona
- Wet days73rd driest of 378
- Comfortable days320th most of 342
What to pack for San Tan Valley in September
- Light, breathable clothing – highs near 101°F and about 2 muggy days
- Layers – afternoons near 101°F but nights near 70°F
Heating and cooling
September has 0 heating degree days and 607 cooling degree days (base 65°F), 12% of the year's total heating and cooling demand.
Questions
How hot is San Tan Valley in September?
The normal high is 101°F and the normal low is 70°F. From 1991 to 2020 the hottest September reading was 115°F (September 1, 1995).
Does it rain a lot in San Tan Valley in September?
About 3 days in September have at least 0.01 in of precipitation, and the normal total is 0.7 in. The wettest September in 1991-2020 was in 1999 (2.9 in); the driest was in 2001, with no measurable precipitation.
Is September a good time to visit San Tan Valley?
September ranks 12th of 12 months on our comfort score for San Tan Valley (33 out of 100). It has almost no comfortable days and about 29 days at 90°F or hotter. The best months are January, February and December.
Where the numbers come from
- Temperature, rain, snowfall and snow depth: Casa Grande Nm (USC00021314), 14 mi S of the city center, 1,419 ft (103 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Frost dates: Chandler Heights (USC00021514), 9.0 mi W of the city center, 1,425 ft (97 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Phoenix Sky Harbor Intl Airport (USW00023183), 32 mi WNW of the city center, 1,107 ft (415 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Phoenix Sky Harbor Intl Airport (722780-23183), 32 mi WNW of the city center, 1,113 ft (409 ft lower than the city). Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).