September is one of the cooler months of the year in Bordertown, with average highs near 17.5°C and lows around 6.5°C (mean 12°C). It is about average for rainfall, averaging 47 mm of rainfall and 76% relative humidity across the period.
September is one of the cooler months of the year in Bordertown. Across 45 years of records, the warmest September in Bordertown was 2023 — when the month averaged 15.1°C — while the coldest was 1992 at 9.5°C. Typical September days reach 17.5°C with nights near 6.5°C. The long-term trend is warming, about 0.5°C per decade.
September is about average for rainfall in Bordertown, averaging 47 mm of rainfall. The wettest September on record was 1996 with 107 mm, while the driest was 2018 at 9 mm.
Relative humidity in Bordertown during September averages 76%. The most humid September was 1992 at 84%, and the least humid was 2023 at 62%.
September receives about 4.3 kWh/m²/day of solar energy in Bordertown. The sunniest September was 2023 at 5 kWh/m²/day, and the cloudiest was 2016 at 3.6.
Average wind speed in Bordertown during September is 3.1 m/s. The windiest September was 1996 at 3.9 m/s, while the calmest was 1997 at 2.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.3°C | 11.4°C | 12.1°C | 12.3°C | 13.2°C | +1.9°C |
| Avg High | 16.7°C | 16.6°C | 17.6°C | 18.0°C | 19.0°C | +2.3°C |
| Avg Low | 6.0°C | 6.2°C | 6.6°C | 6.7°C | 7.4°C | +1.4°C |
| Avg Rain | 48 mm | 65 mm | 52 mm | 33 mm | 30 mm | -18 mm |
September temperatures in Bordertown have risen by about 2.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 0.1°C (1983) to a record high of 31.4°C (2023).
Rainfall in September is about average for rainfall, averaging 47 mm, with a wettest year of 107 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.7°C per decade while lows rose 0.3°C per decade, widening the gap between day and night.
A quieter season to visit Bordertown
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Bordertown. That said, September — with days averaging 17.5°C and nights around 6.5°C (mean 12°C) and moderate rainfall (47 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 18.5°C | 13.0°C | 7.4°C | 27.7°C | 1.5°C | 29 mm | 70% | 3.5 m/s | 4.3 |
| 2024 | 18.8°C | 13.3°C | 7.7°C | 24.7°C | 2.5°C | 28 mm | 69% | 3.5 m/s | 4.2 |
| 2023 🔥 | 22.0°C | 15.1°C | 8.1°C | 31.4°C | 4.7°C | 14 mm | 62% | 2.9 m/s | 5 |
| 2022 | 17.1°C | 11.8°C | 6.6°C | 21.9°C | 2.5°C | 47 mm | 78% | 3 m/s | 4 |
| 2021 | 19.0°C | 13.0°C | 7.1°C | 29.1°C | 2.7°C | 20 mm | 69% | 3.3 m/s | 4.3 |
| 2020 | 18.8°C | 13.1°C | 7.4°C | 24.9°C | 2.4°C | 41 mm | 71% | 3.4 m/s | 4.3 |
| 2019 | 19.1°C | 12.6°C | 6.1°C | 26.9°C | 1.1°C | 19 mm | 65% | 2.9 m/s | 4.6 |
| 2018 | 18.5°C | 12.1°C | 5.7°C | 26.7°C | 1.9°C | 9 mm | 65% | 3 m/s | 4.7 |
| 2017 | 18.7°C | 13.1°C | 7.5°C | 28.6°C | 2.6°C | 17 mm | 65% | 3.8 m/s | 4.5 |
| 2016 | 16.6°C | 11.5°C | 6.5°C | 23.2°C | 3.2°C | 64 mm | 79% | 2.8 m/s | 3.6 |
| 2015 | 19.3°C | 12.8°C | 6.3°C | 28.0°C | 2.4°C | 12 mm | 66% | 2.7 m/s | 4.5 |
| 2014 | 18.9°C | 12.9°C | 6.8°C | 28.3°C | 3.3°C | 23 mm | 72% | 2.9 m/s | 4.7 |
| 2013 | 18.5°C | 13.5°C | 8.4°C | 24.4°C | 5.5°C | 55 mm | 82% | 3.2 m/s | 3.9 |
| 2012 | 17.3°C | 11.9°C | 6.5°C | 24.3°C | 2.4°C | 33 mm | 76% | 3.2 m/s | 4.3 |
| 2011 | 18.0°C | 12.4°C | 6.8°C | 26.0°C | 2.3°C | 47 mm | 75% | 3 m/s | 4.4 |
| 2010 | 15.3°C | 10.6°C | 6.0°C | 18.0°C | 1.5°C | 53 mm | 83% | 2.7 m/s | 3.8 |
| 2009 | 17.4°C | 12.1°C | 6.9°C | 26.3°C | 3.4°C | 71 mm | 76% | 3.3 m/s | 3.9 |
| 2008 | 17.9°C | 12.0°C | 6.1°C | 29.0°C | 1.6°C | 31 mm | 74% | 3.1 m/s | 4.7 |
| 2007 | 18.5°C | 12.7°C | 6.8°C | 25.1°C | 2.4°C | 45 mm | 70% | 3.6 m/s | 4.5 |
| 2006 | 19.8°C | 13.1°C | 6.5°C | 28.9°C | 2.4°C | 36 mm | 65% | 3.2 m/s | 4.6 |
| 2005 | 17.7°C | 12.2°C | 6.8°C | 24.8°C | 2.4°C | 37 mm | 74% | 2.8 m/s | 4.3 |
| 2004 | 16.4°C | 11.2°C | 6.1°C | 25.8°C | 1.4°C | 41 mm | 82% | 2.5 m/s | 4 |
| 2003 | 15.6°C | 10.6°C | 5.5°C | 23.3°C | 0.6°C | 48 mm | 80% | 3.7 m/s | 4.4 |
| 2002 | 17.3°C | 11.9°C | 6.6°C | 26.5°C | 2.5°C | 47 mm | 71% | 3.6 m/s | 4.2 |
| 2001 | 18.0°C | 12.6°C | 7.2°C | 25.2°C | 3.4°C | 84 mm | 79% | 2.9 m/s | 4.1 |
| 2000 | 16.9°C | 12.1°C | 7.3°C | 22.8°C | 2.6°C | 79 mm | 83% | 3.5 m/s | 4 |
| 1999 | 19.2°C | 13.4°C | 7.6°C | 28.8°C | 3.6°C | 51 mm | 74% | 2.9 m/s | 4.4 |
| 1998 | 18.0°C | 12.5°C | 7.0°C | 24.1°C | 2.9°C | 81 mm | 79% | 3.1 m/s | 4.3 |
| 1997 | 16.9°C | 11.6°C | 6.4°C | 20.4°C | 3.4°C | 71 mm | 81% | 2.4 m/s | 4.3 |
| 1996 🌧️ | 15.2°C | 10.8°C | 6.3°C | 24.0°C | 2.1°C | 107 mm | 80% | 3.9 m/s | 4.2 |
| 1995 | 16.4°C | 11.1°C | 5.7°C | 21.8°C | 0.4°C | 20 mm | 81% | 2.7 m/s | 4.3 |
| 1994 | 15.7°C | 10.5°C | 5.2°C | 21.7°C | 0.3°C | 28 mm | 75% | 3 m/s | 4.3 |
| 1993 | 17.5°C | 11.8°C | 6.1°C | 25.6°C | 3.1°C | 62 mm | 77% | 2.7 m/s | 4.4 |
| 1992 ❄️ | 13.9°C | 9.5°C | 5.1°C | 16.9°C | 1.7°C | 101 mm | 84% | 2.6 m/s | 3.8 |
| 1991 | 16.1°C | 11.2°C | 6.2°C | 21.1°C | 2.8°C | 73 mm | 82% | 3.1 m/s | 4.2 |
| 1990 | 17.2°C | 12.0°C | 6.8°C | 24.1°C | 2.3°C | 57 mm | 79% | 3 m/s | 4.7 |
| 1989 | 16.5°C | 11.3°C | 6.1°C | 23.2°C | 4.2°C | 50 mm | 82% | 2.9 m/s | 4.4 |
| 1988 | 17.5°C | 12.1°C | 6.8°C | 25.2°C | 2.6°C | 68 mm | 79% | 3.1 m/s | 4.2 |
| 1987 | 17.7°C | 12.0°C | 6.4°C | 29.2°C | 1.5°C | 14 mm | 77% | 2.7 m/s | 4.5 |
| 1986 | 16.0°C | 11.2°C | 6.4°C | 22.3°C | 3.0°C | 59 mm | 82% | 3 m/s | 4.3 |
| 1985 | 16.4°C | 10.6°C | 4.8°C | 23.0°C | 2.4°C | 28 mm | 78% | 2.7 m/s | 4.7 |
| 1984 | 14.5°C | 9.6°C | 4.7°C | 20.4°C | 1.4°C | 72 mm | 80% | 3.1 m/s | 4.1 |
| 1983 | 16.2°C | 11.1°C | 6.0°C | 23.4°C | 0.1°C | 77 mm | 81% | 3.3 m/s | — |
| 1982 | 18.1°C | 11.7°C | 5.3°C | 25.3°C | 2.3°C | 28 mm | 67% | 3.1 m/s | — |
| 1981 | 17.5°C | 12.4°C | 7.3°C | 25.4°C | 3.6°C | 33 mm | 82% | 2.9 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.5°C with lows near 6.5°C (mean 12°C), based on 45 years of NASA POWER data.
September averages 47 mm of rainfall in Bordertown, about average for rainfall. The wettest on record was 107 mm in 1996.
The hottest September reached 31.4°C in 2023. The coldest dipped to 0.1°C in 1983.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.1°C. Daytime highs moved from 16.5°C to 19.1°C and overnight lows from 5.6°C to 7.4°C over the same span.
September is one of the cooler months of the year in Bordertown and about average for rainfall, so plan for around 17.5°C daytime highs and 6.5°C at night.
Not quite — September is the 4th coolest month in Bordertown, averaging 12°C.
For September in Bordertown, pack warm layers and a jacket for chilly mornings, with typical highs of 17.5°C and lows of 6.5°C.
Relative humidity in September averages 76% — quite humid.
Average wind speed in September is 3.1 m/s. The windiest September on record averaged 3.9 m/s (1996).
The wettest September on record was 1996 with 107 mm. On average, September sees 47 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 Bordertown 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.
