September is one of the warmer months of the year in Spring Valley, with average highs near 24.5°C and lows around 14°C (mean 19.3°C). It is about average for rainfall, averaging 107 mm of rainfall and 74% relative humidity across the period.
September is one of the warmer months of the year in Spring Valley. Across 45 years of records, the warmest September in Spring Valley was 2005 — when the month averaged 22.1°C — while the coldest was 1984 at 16.3°C. Typical September days reach 24.5°C with nights near 14°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Spring Valley, averaging 107 mm of rainfall. The wettest September on record was 2023 with 254 mm, while the driest was 2024 at 27 mm.
Relative humidity in Spring Valley during September averages 74%. The most humid September was 2011 at 87%, and the least humid were 1983 and 2005 at 63%.
September receives about 4.1 kWh/m²/day of solar energy in Spring Valley. The sunniest Septembers were 2005, 2007 and 2013, among others at 4.8 kWh/m²/day, and the cloudiest was 2018 at 3.
Average wind speed in Spring Valley during September is 1.4 m/s. The windiest September was 2010 at 1.6 m/s, while the calmest were 1982 and 2025 at 1.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 18.4°C | 18.5°C | 19.3°C | 20.2°C | 20.0°C | +1.6°C |
| Avg High | 23.9°C | 23.8°C | 24.6°C | 25.5°C | 25.1°C | +1.2°C |
| Avg Low | 12.8°C | 13.3°C | 14.0°C | 15.0°C | 15.0°C | +2.2°C |
| Avg Rain | 95 mm | 112 mm | 112 mm | 100 mm | 123 mm | +28 mm |
September temperatures in Spring Valley have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 3.1°C (2000) to a record high of 34.8°C (2015).
Rainfall in September is about average for rainfall, averaging 107 mm, with a wettest year of 254 mm.
One of the best times to visit Spring Valley
September is one of the best times to visit Spring Valley. Expect days averaging 24.5°C and nights around 14°C (mean 19.3°C) — warmer than Spring Valley's yearly average — with higher rainfall (107 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 26.6°C | 21.1°C | 15.5°C | 30.4°C | 11.3°C | 62 mm | 71% | 1.2 m/s | 4.4 |
| 2024 | 25.2°C | 19.8°C | 14.5°C | 29.8°C | 10.2°C | 27 mm | 73% | 1.3 m/s | 4.3 |
| 2023 🌧️ | 24.7°C | 20.0°C | 15.4°C | 34.4°C | 8.9°C | 254 mm | 80% | 1.4 m/s | 4 |
| 2022 | 25.2°C | 20.0°C | 14.8°C | 30.9°C | 6.6°C | 117 mm | 72% | 1.3 m/s | 4.1 |
| 2021 | 24.1°C | 19.7°C | 15.4°C | 28.2°C | 9.8°C | 192 mm | 82% | 1.5 m/s | 4.1 |
| 2020 | 24.8°C | 19.5°C | 14.2°C | 30.1°C | 5.7°C | 86 mm | 73% | 1.4 m/s | 4.2 |
| 2019 | 26.1°C | 20.3°C | 14.6°C | 31.0°C | 7.7°C | 27 mm | 70% | 1.3 m/s | 4.2 |
| 2018 | 24.8°C | 20.8°C | 16.8°C | 33.7°C | 9.4°C | 191 mm | 85% | 1.3 m/s | 3 |
| 2017 | 25.5°C | 20.3°C | 15.1°C | 32.9°C | 9.4°C | 61 mm | 74% | 1.4 m/s | 4.4 |
| 2016 | 26.5°C | 21.2°C | 16.0°C | 32.6°C | 8.4°C | 60 mm | 69% | 1.4 m/s | 4.5 |
| 2015 | 27.7°C | 21.8°C | 15.9°C | 34.8°C | 10.0°C | 101 mm | 71% | 1.3 m/s | 4.6 |
| 2014 | 25.6°C | 20.0°C | 14.4°C | 33.1°C | 8.1°C | 33 mm | 68% | 1.3 m/s | 4.4 |
| 2013 | 24.2°C | 18.1°C | 12.1°C | 33.3°C | 5.9°C | 58 mm | 70% | 1.3 m/s | 4.8 |
| 2012 | 24.2°C | 19.2°C | 14.2°C | 32.3°C | 8.5°C | 137 mm | 76% | 1.4 m/s | 4.1 |
| 2011 | 23.6°C | 19.6°C | 15.6°C | 27.3°C | 7.1°C | 232 mm | 87% | 1.3 m/s | 3.4 |
| 2010 | 26.3°C | 20.8°C | 15.2°C | 34.6°C | 8.5°C | 102 mm | 69% | 1.6 m/s | 4.2 |
| 2009 | 23.2°C | 18.1°C | 13.1°C | 28.7°C | 7.3°C | 57 mm | 75% | 1.4 m/s | 4.1 |
| 2008 | 24.4°C | 19.4°C | 14.4°C | 33.0°C | 8.2°C | 179 mm | 78% | 1.3 m/s | 4.2 |
| 2007 | 26.4°C | 20.5°C | 14.6°C | 31.5°C | 8.2°C | 31 mm | 70% | 1.3 m/s | 4.8 |
| 2006 | 22.6°C | 17.9°C | 13.3°C | 27.3°C | 7.1°C | 104 mm | 80% | 1.4 m/s | 3.6 |
| 2005 🔥 | 28.3°C | 22.1°C | 15.8°C | 34.0°C | 8.1°C | 37 mm | 63% | 1.3 m/s | 4.8 |
| 2004 | 24.2°C | 19.5°C | 14.8°C | 29.2°C | 7.7°C | 220 mm | 81% | 1.3 m/s | 4 |
| 2003 | 23.1°C | 18.9°C | 14.6°C | 26.9°C | 7.1°C | 176 mm | 83% | 1.5 m/s | 3.7 |
| 2002 | 25.6°C | 20.1°C | 14.6°C | 33.8°C | 9.3°C | 111 mm | 72% | 1.4 m/s | 4.5 |
| 2001 | 24.6°C | 18.8°C | 12.9°C | 30.1°C | 7.4°C | 95 mm | 70% | 1.4 m/s | 4.5 |
| 2000 | 23.3°C | 17.8°C | 12.3°C | 29.7°C | 3.1°C | 107 mm | 75% | 1.3 m/s | 4 |
| 1999 | 24.0°C | 19.2°C | 14.4°C | 31.3°C | 7.2°C | 242 mm | 79% | 1.5 m/s | 4 |
| 1998 | 26.2°C | 20.1°C | 14.1°C | 31.5°C | 5.8°C | 65 mm | 69% | 1.3 m/s | 4.3 |
| 1997 | 23.7°C | 18.2°C | 12.7°C | 29.2°C | 5.3°C | 67 mm | 71% | 1.5 m/s | 4.4 |
| 1996 | 23.4°C | 18.8°C | 14.2°C | 31.2°C | 7.4°C | 152 mm | 78% | 1.5 m/s | 3.5 |
| 1995 | 24.1°C | 18.5°C | 12.9°C | 30.3°C | 6.5°C | 99 mm | 66% | 1.4 m/s | 4.1 |
| 1994 | 23.3°C | 17.9°C | 12.5°C | 28.9°C | 8.7°C | 86 mm | 73% | 1.5 m/s | 4 |
| 1993 | 23.7°C | 18.7°C | 13.8°C | 31.0°C | 5.2°C | 143 mm | 75% | 1.4 m/s | 3.2 |
| 1992 | 23.0°C | 18.0°C | 13.0°C | 28.2°C | 4.8°C | 92 mm | 76% | 1.5 m/s | 3.9 |
| 1991 | 23.9°C | 18.3°C | 12.8°C | 33.6°C | 3.2°C | 115 mm | 69% | 1.4 m/s | 4.3 |
| 1990 | 23.1°C | 17.8°C | 12.4°C | 29.7°C | 4.2°C | 58 mm | 76% | 1.3 m/s | 4.2 |
| 1989 | 23.6°C | 18.6°C | 13.5°C | 33.1°C | 3.3°C | 165 mm | 78% | 1.4 m/s | 3.9 |
| 1988 | 23.5°C | 17.6°C | 11.7°C | 27.9°C | 6.1°C | 73 mm | 71% | 1.3 m/s | 4.4 |
| 1987 | 22.5°C | 17.9°C | 13.3°C | 26.9°C | 5.8°C | 155 mm | 82% | 1.3 m/s | 3.9 |
| 1986 | 23.8°C | 18.3°C | 12.8°C | 29.8°C | 5.6°C | 50 mm | 72% | 1.4 m/s | 3.7 |
| 1985 | 25.2°C | 19.4°C | 13.6°C | 32.6°C | 6.9°C | 131 mm | 70% | 1.3 m/s | 4.4 |
| 1984 ❄️ | 21.8°C | 16.3°C | 10.7°C | 28.6°C | 5.0°C | 55 mm | 74% | 1.3 m/s | 4.8 |
| 1983 | 26.6°C | 20.1°C | 13.7°C | 34.6°C | 6.0°C | 77 mm | 63% | 1.3 m/s | — |
| 1982 | 24.8°C | 18.9°C | 13.1°C | 30.6°C | 9.1°C | 60 mm | 69% | 1.2 m/s | — |
| 1981 | 23.4°C | 18.1°C | 12.8°C | 30.6°C | 4.5°C | 92 mm | 69% | 1.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 24.5°C with lows near 14°C (mean 19.3°C), based on 45 years of NASA POWER data.
September averages 107 mm of rainfall in Spring Valley, about average for rainfall. The wettest on record was 254 mm in 2023.
The hottest September reached 34.8°C in 2015. The coldest dipped to 3.1°C in 2000.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.5°C. Daytime highs moved from 24.4°C to 25.2°C and overnight lows from 12.8°C to 15.1°C over the same span.
September is one of the warmer months of the year in Spring Valley and about average for rainfall, so plan for around 24.5°C daytime highs and 14°C at night.
Not quite — September is the 9th coolest month in Spring Valley, averaging 19.3°C.
For September in Spring Valley, pack light layers you can adjust through the day, with typical highs of 24.5°C and lows of 14°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 74% — moderately humid.
Average wind speed in September is 1.4 m/s. The windiest September on record averaged 1.6 m/s (2010).
The wettest September on record was 2023 with 254 mm. On average, September sees 107 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 Spring Valley 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.
