Climate averages 1991–2020
Surprise weather
in September.
A very hot, fairly dry month: the 4th warmest and the 6th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a very hot month in Surprise: daytime highs average 36.6°C and nights cool to about 23.4°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 20 mm of rain on roughly 3 days, which makes September a fairly dry month (the 6th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 25 min on an average September day.
The nearest other city in this atlas is Peoria (Arizona), United States (10 km away). In September its highs average 36.6°C, about as warm as Surprise, with 22 mm of rain.
Among the 498 cities listed in the United States, Surprise ranks joint 9th of 498 for the warmest September highs and joint 119th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Surprise is 9.7°C warmer than that mean.
From September to October, average highs fall by 6.2°C to 30.4°C, and monthly rainfall falls from 20 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
Surprise climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 18.3°C5.0°C | 5.0°C | 35 | 3.6 | 10.210 h |
| February | 20.1°C6.5°C | 6.5°C | 41 | 4.3 | 11.011 h |
| March | 24.3°C9.6°C | 9.6°C | 27 | 3.1 | 12.012 h |
| April | 28.8°C13.6°C | 13.6°C | 8.6 | 1.3 | 13.013 h |
| May | 33.7°C19.1°C | 19.1°C | 3.3 | 0.7 | 13.914 h |
| June | 39.2°C24.4°C | 24.4°C | 1.7 | 0.3 | 14.314 h |
| July | 40.4°C28.1°C | 28.1°C | 17 | 3.0 | 14.214 h |
| August | 39.4°C27.6°C | 27.6°C | 23 | 3.8 | 13.413 h |
| September, selected | 36.6°C23.4°C | 23.4°C | 20 | 3.1 | 12.412 h |
| October | 30.4°C16.3°C | 16.3°C | 18 | 2.1 | 11.411 h |
| November | 23.4°C9.6°C | 9.6°C | 21 | 2.2 | 10.510 h |
| December | 17.5°C4.9°C | 4.9°C | 31 | 3.4 | 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
- Peoria (Arizona), United States in SeptemberUnited States · 10 kmHigh 36.6°C · Low 23.4°C · 22 mm rain
- Glendale (Arizona), United States in SeptemberUnited States · 17 kmHigh 36.8°C · Low 23.5°C · 22 mm rain
- Avondale in SeptemberUnited States · 22 kmHigh 37.4°C · Low 23.9°C · 22 mm rain
- Goodyear in SeptemberUnited States · 22 kmHigh 37.4°C · Low 24.0°C · 22 mm rain
- Phoenix in SeptemberUnited States · 31 kmHigh 36.9°C · Low 23.4°C · 24 mm rain
- Scottsdale in SeptemberUnited States · 42 kmHigh 36.5°C · Low 23.1°C · 24 mm rain
- Tempe in SeptemberUnited States · 46 kmHigh 36.8°C · Low 23.2°C · 24 mm rain
- Mesa in SeptemberUnited States · 53 kmHigh 36.6°C · Low 22.8°C · 26 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 Surprise) is explained once on the Surprise year overview and on the Sources, method and limits page.