September is one of the warmer months of the year in Alma, with average highs near 17.2°C and lows around 8.5°C (mean 12.9°C). It is a relatively wet time of year, averaging 88 mm of rainfall and 80% relative humidity across the period.
September is one of the warmer months of the year in Alma. Across 45 years of records, the warmest September in Alma was 2024 — when the month averaged 16.2°C — while the coldest were 1986 and 1991 at 10°C. Typical September days reach 17.2°C with nights near 8.5°C. The long-term trend is warming, about 0.7°C per decade.
September is a relatively wet time of year in Alma, averaging 88 mm of rainfall. The wettest September on record was 2010 with 197 mm, while the driest was 2025 at 39 mm.
Relative humidity in Alma during September averages 80%. The most humid September was 1994 at 84%, and the least humid was 2022 at 76%.
September receives about 3.3 kWh/m²/day of solar energy in Alma. The sunniest September was 2022 at 3.9 kWh/m²/day, and the cloudiest was 1997 at 2.7.
Average wind speed in Alma during September is 2.3 m/s. The windiest September was 2007 at 2.7 m/s, while the calmest was 2023 at 1.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.7°C | 11.9°C | 13.3°C | 13.6°C | 14.2°C | +2.5°C |
| Avg High | 15.9°C | 16.3°C | 17.7°C | 17.9°C | 18.7°C | +2.8°C |
| Avg Low | 7.4°C | 7.5°C | 8.8°C | 9.3°C | 9.7°C | +2.3°C |
| Avg Rain | 81 mm | 87 mm | 94 mm | 98 mm | 74 mm | -6 mm |
September temperatures in Alma have risen by about 2.7°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -2.7°C (2000) to a record high of 29.5°C (2010).
Rainfall in September is a relatively wet time of year, averaging 88 mm, with a wettest year of 197 mm.
One of the best times to visit Alma
September is one of the best times to visit Alma. Expect days averaging 17.2°C and nights around 8.5°C (mean 12.9°C) — warmer than Alma's yearly average — with higher rainfall (88 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 | 18.4°C | 13.7°C | 8.9°C | 24.8°C | 2.9°C | 39 mm | 78% | 2.1 m/s | 3.7 |
| 2024 🔥 | 20.7°C | 16.2°C | 11.7°C | 26.2°C | 6.7°C | 46 mm | 78% | 2.2 m/s | 3.7 |
| 2023 | 20.7°C | 16.1°C | 11.6°C | 29.0°C | 6.1°C | 68 mm | 79% | 1.6 m/s | 3.8 |
| 2022 | 18.4°C | 13.6°C | 8.8°C | 25.4°C | 3.0°C | 70 mm | 76% | 2.2 m/s | 3.9 |
| 2021 | 17.8°C | 13.7°C | 9.6°C | 23.3°C | 5.4°C | 93 mm | 81% | 2.3 m/s | 3.1 |
| 2020 | 16.0°C | 11.8°C | 7.6°C | 22.1°C | 0.1°C | 131 mm | 81% | 2.4 m/s | 3.1 |
| 2019 | 16.2°C | 12.0°C | 7.9°C | 23.3°C | 2.0°C | 113 mm | 81% | 2.1 m/s | 3.1 |
| 2018 | 18.1°C | 13.5°C | 9.0°C | 25.9°C | -0.2°C | 77 mm | 79% | 2.4 m/s | 3.6 |
| 2017 | 19.1°C | 15.1°C | 11.2°C | 27.8°C | 3.5°C | 75 mm | 82% | 1.9 m/s | 3.3 |
| 2016 | 18.6°C | 14.3°C | 10.1°C | 26.0°C | 3.4°C | 61 mm | 81% | 2.3 m/s | 3.4 |
| 2015 | 20.3°C | 15.9°C | 11.4°C | 26.8°C | 3.3°C | 64 mm | 80% | 2.1 m/s | 3.8 |
| 2014 | 16.7°C | 12.3°C | 7.8°C | 24.9°C | -0.8°C | 98 mm | 81% | 2.4 m/s | 3.1 |
| 2013 | 16.9°C | 12.5°C | 8.2°C | 23.1°C | 1.4°C | 94 mm | 81% | 2.5 m/s | 3.1 |
| 2012 | 17.7°C | 13.3°C | 9.0°C | 24.8°C | 2.8°C | 123 mm | 80% | 2.4 m/s | 3.3 |
| 2011 | 18.7°C | 14.2°C | 9.6°C | 23.5°C | 4.5°C | 77 mm | 82% | 2.2 m/s | 3.7 |
| 2010 🌧️ | 16.4°C | 12.8°C | 9.2°C | 29.5°C | 3.6°C | 197 mm | 81% | 2.3 m/s | 2.9 |
| 2009 | 17.4°C | 12.9°C | 8.3°C | 23.1°C | 2.0°C | 57 mm | 80% | 2.2 m/s | 3.7 |
| 2008 | 17.6°C | 13.1°C | 8.6°C | 27.6°C | 1.8°C | 91 mm | 81% | 2 m/s | 3 |
| 2007 | 17.7°C | 12.9°C | 8.2°C | 26.6°C | 2.7°C | 73 mm | 77% | 2.7 m/s | 3.5 |
| 2006 | 16.8°C | 12.4°C | 8.1°C | 23.7°C | 3.0°C | 176 mm | 79% | 2.1 m/s | 3.4 |
| 2005 | 18.0°C | 13.8°C | 9.6°C | 26.0°C | 4.1°C | 104 mm | 79% | 2.5 m/s | 3.3 |
| 2004 | 18.1°C | 13.3°C | 8.5°C | 23.9°C | 4.6°C | 91 mm | 80% | 2.3 m/s | 3.5 |
| 2003 | 19.2°C | 14.9°C | 10.6°C | 26.2°C | 6.7°C | 77 mm | 80% | 2.2 m/s | 3.4 |
| 2002 | 18.8°C | 14.4°C | 10.0°C | 28.4°C | 4.0°C | 84 mm | 78% | 2.4 m/s | 3.6 |
| 2001 | 17.7°C | 13.6°C | 9.6°C | 27.4°C | 4.3°C | 101 mm | 81% | 2.3 m/s | 3.4 |
| 2000 | 15.5°C | 11.2°C | 6.9°C | 23.7°C | -2.7°C | 83 mm | 78% | 2.5 m/s | 3 |
| 1999 | 20.0°C | 15.6°C | 11.3°C | 28.2°C | 4.7°C | 98 mm | 80% | 2.2 m/s | 3.3 |
| 1998 | 16.6°C | 12.4°C | 8.3°C | 21.1°C | 2.4°C | 121 mm | 81% | 2.4 m/s | 3.1 |
| 1997 | 16.1°C | 12.0°C | 8.0°C | 23.7°C | 1.3°C | 82 mm | 82% | 2.5 m/s | 2.7 |
| 1996 | 17.3°C | 13.1°C | 8.9°C | 25.6°C | 1.4°C | 107 mm | 80% | 2.1 m/s | 3.4 |
| 1995 | 15.1°C | 10.1°C | 5.1°C | 21.9°C | 1.4°C | 63 mm | 77% | 2.4 m/s | 3.4 |
| 1994 | 16.5°C | 12.0°C | 7.5°C | 21.4°C | 2.9°C | 79 mm | 84% | 2 m/s | 3.3 |
| 1993 | 15.2°C | 10.6°C | 6.0°C | 23.0°C | -1.1°C | 77 mm | 79% | 2.3 m/s | 2.9 |
| 1992 | 17.0°C | 12.3°C | 7.6°C | 24.1°C | -1.2°C | 95 mm | 81% | 2.4 m/s | 3.1 |
| 1991 | 14.3°C | 10.0°C | 5.6°C | 21.8°C | -1.5°C | 44 mm | 77% | 2.2 m/s | 3.4 |
| 1990 | 15.3°C | 10.8°C | 6.3°C | 23.9°C | 1.0°C | 109 mm | 79% | 2.4 m/s | 3.3 |
| 1989 | 17.4°C | 12.7°C | 8.0°C | 25.2°C | 0.1°C | 73 mm | 78% | 2.4 m/s | 3.7 |
| 1988 | 14.7°C | 10.7°C | 6.8°C | 21.4°C | 0.7°C | 104 mm | 83% | 2.6 m/s | 3 |
| 1987 | 15.8°C | 11.7°C | 7.6°C | 23.8°C | 0.7°C | 99 mm | 83% | 2.2 m/s | 3.2 |
| 1986 ❄️ | 14.5°C | 10.0°C | 5.6°C | 21.3°C | 0.7°C | 111 mm | 80% | 2.3 m/s | 3.2 |
| 1985 | 17.1°C | 12.6°C | 8.1°C | 25.6°C | 3.4°C | 66 mm | 80% | 2.1 m/s | 3.5 |
| 1984 | 14.4°C | 10.1°C | 5.9°C | 21.9°C | 0.4°C | 47 mm | 78% | 2.5 m/s | 3.8 |
| 1983 | 17.0°C | 13.0°C | 9.0°C | 27.4°C | 2.3°C | 97 mm | 81% | 2.2 m/s | — |
| 1982 | 16.5°C | 12.2°C | 7.9°C | 25.1°C | 1.5°C | 65 mm | 81% | 2.1 m/s | — |
| 1981 | 16.1°C | 12.0°C | 7.9°C | 25.0°C | 2.0°C | 65 mm | 81% | 2.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.2°C with lows near 8.5°C (mean 12.9°C), based on 45 years of NASA POWER data.
September averages 88 mm of rainfall in Alma, a relatively wet time of year. The wettest on record was 197 mm in 2010.
The hottest September reached 29.5°C in 2010. The coldest dipped to -2.7°C in 2000.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.7°C. Daytime highs moved from 16.2°C to 19.2°C and overnight lows from 7.8°C to 10.1°C over the same span.
September is one of the warmer months of the year in Alma and a relatively wet time of year, so plan for around 17.2°C daytime highs and 8.5°C at night.
Not quite — September is the 9th coolest month in Alma, averaging 12.9°C.
For September in Alma, pack light layers you can adjust through the day, with typical highs of 17.2°C and lows of 8.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 80% — quite humid.
Average wind speed in September is 2.3 m/s. The windiest September on record averaged 2.7 m/s (2007).
The wettest September on record was 2010 with 197 mm. On average, September sees 88 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 Alma 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.
