September is one of the warmer months of the year in Brockton, with average highs near 23.8°C and lows around 12.9°C (mean 18.4°C). It is about average for rainfall, averaging 100 mm of rainfall and 75% relative humidity across the period.
September is one of the warmer months of the year in Brockton. Across 45 years of records, the warmest September in Brockton was 2015 — when the month averaged 21°C — while the coldest was 1984 at 16.2°C. Typical September days reach 23.8°C with nights near 12.9°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Brockton, averaging 100 mm of rainfall. The wettest September on record was 2008 with 216 mm, while the driest was 1986 at 30 mm.
Relative humidity in Brockton during September averages 75%. The most humid September was 2011 at 84%, and the least humid was 1983 at 64%.
September receives about 4.2 kWh/m²/day of solar energy in Brockton. The sunniest Septembers were 1984, 2007 and 2015 at 4.7 kWh/m²/day, and the cloudiest were 1993, 1996 and 2018 at 3.5.
Average wind speed in Brockton during September is 0.4 m/s. The windiest Septembers were 2023, 2024 and 2025, among others at 0.4 m/s, while the calmest was 2011 at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.3°C | 17.6°C | 18.5°C | 19.3°C | 19.1°C | +1.8°C |
| Avg High | 23.0°C | 22.9°C | 24.1°C | 24.7°C | 24.3°C | +1.3°C |
| Avg Low | 11.7°C | 12.2°C | 13.0°C | 13.8°C | 14.0°C | +2.3°C |
| Avg Rain | 78 mm | 114 mm | 100 mm | 97 mm | 117 mm | +39 mm |
September temperatures in Brockton have risen by about 1.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 2.3°C (1991) to a record high of 35.6°C (2002).
Rainfall in September is about average for rainfall, averaging 100 mm, with a wettest year of 216 mm.
One of the best times to visit Brockton
September is one of the best times to visit Brockton. Expect days averaging 23.8°C and nights around 12.9°C (mean 18.4°C) — warmer than Brockton's yearly average — with higher rainfall (100 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 | 25.0°C | 19.5°C | 14.0°C | 29.9°C | 9.2°C | 92 mm | 75% | 0.4 m/s | 4.5 |
| 2024 | 24.5°C | 19.0°C | 13.5°C | 30.4°C | 10.9°C | 60 mm | 74% | 0.4 m/s | 4.3 |
| 2023 | 23.6°C | 19.3°C | 15.1°C | 34.0°C | 8.9°C | 177 mm | 83% | 0.4 m/s | 3.8 |
| 2022 | 23.8°C | 18.6°C | 13.4°C | 31.4°C | 7.8°C | 130 mm | 76% | 0.4 m/s | 4.1 |
| 2021 | 23.7°C | 19.2°C | 14.6°C | 27.7°C | 9.2°C | 206 mm | 81% | 0.4 m/s | 4 |
| 2020 | 25.0°C | 19.2°C | 13.5°C | 32.3°C | 6.2°C | 35 mm | 68% | 0.4 m/s | 4.4 |
| 2019 | 24.3°C | 18.6°C | 12.9°C | 30.5°C | 7.3°C | 45 mm | 72% | 0.4 m/s | 4.5 |
| 2018 | 24.4°C | 19.7°C | 15.0°C | 35.0°C | 9.0°C | 190 mm | 80% | 0.4 m/s | 3.5 |
| 2017 | 25.0°C | 19.6°C | 14.2°C | 31.1°C | 8.0°C | 98 mm | 76% | 0.4 m/s | 4.1 |
| 2016 | 25.5°C | 20.2°C | 14.9°C | 34.4°C | 5.9°C | 64 mm | 71% | 0.4 m/s | 4.1 |
| 2015 🔥 | 27.1°C | 21.0°C | 14.9°C | 35.4°C | 7.7°C | 121 mm | 73% | 0.4 m/s | 4.7 |
| 2014 | 25.0°C | 19.1°C | 13.2°C | 32.4°C | 6.3°C | 32 mm | 70% | 0.4 m/s | 4.5 |
| 2013 | 23.2°C | 17.4°C | 11.5°C | 34.1°C | 6.4°C | 71 mm | 74% | 0.4 m/s | 4.6 |
| 2012 | 23.2°C | 18.0°C | 12.7°C | 28.6°C | 7.2°C | 122 mm | 76% | 0.4 m/s | 4.2 |
| 2011 | 23.8°C | 19.1°C | 14.4°C | 28.5°C | 7.1°C | 156 mm | 84% | 0.3 m/s | 4 |
| 2010 | 25.3°C | 20.0°C | 14.6°C | 35.4°C | 8.1°C | 70 mm | 72% | 0.4 m/s | 4.1 |
| 2009 | 22.0°C | 16.8°C | 11.5°C | 27.0°C | 6.0°C | 59 mm | 77% | 0.4 m/s | 4.5 |
| 2008 🌧️ | 23.1°C | 18.2°C | 13.3°C | 31.1°C | 7.0°C | 216 mm | 80% | 0.4 m/s | 4.1 |
| 2007 | 26.1°C | 19.8°C | 13.4°C | 33.1°C | 6.7°C | 58 mm | 68% | 0.4 m/s | 4.7 |
| 2006 | 22.4°C | 17.3°C | 12.1°C | 27.5°C | 5.3°C | 61 mm | 79% | 0.4 m/s | 4 |
| 2005 | 26.1°C | 20.1°C | 14.2°C | 32.6°C | 7.7°C | 77 mm | 71% | 0.4 m/s | 4.5 |
| 2004 | 23.6°C | 18.2°C | 12.9°C | 29.9°C | 6.7°C | 175 mm | 79% | 0.4 m/s | 4.2 |
| 2003 | 23.8°C | 18.7°C | 13.6°C | 28.8°C | 8.4°C | 88 mm | 79% | 0.4 m/s | 3.9 |
| 2002 | 25.6°C | 19.9°C | 14.1°C | 35.6°C | 8.1°C | 110 mm | 74% | 0.4 m/s | 4.3 |
| 2001 | 24.5°C | 18.7°C | 12.9°C | 31.3°C | 7.1°C | 77 mm | 70% | 0.4 m/s | 4.6 |
| 2000 | 23.4°C | 17.5°C | 11.7°C | 30.6°C | 2.8°C | 76 mm | 73% | 0.4 m/s | 4.2 |
| 1999 | 24.2°C | 19.2°C | 14.2°C | 33.7°C | 7.2°C | 187 mm | 78% | 0.4 m/s | 3.9 |
| 1998 | 25.1°C | 18.9°C | 12.7°C | 30.3°C | 4.9°C | 65 mm | 71% | 0.4 m/s | 4.4 |
| 1997 | 23.3°C | 17.7°C | 12.1°C | 28.3°C | 4.7°C | 37 mm | 72% | 0.4 m/s | 4 |
| 1996 | 22.1°C | 17.6°C | 13.2°C | 29.9°C | 6.1°C | 200 mm | 81% | 0.4 m/s | 3.5 |
| 1995 | 23.1°C | 17.2°C | 11.4°C | 30.8°C | 5.3°C | 83 mm | 68% | 0.4 m/s | 4.3 |
| 1994 | 21.7°C | 16.8°C | 11.8°C | 28.1°C | 8.2°C | 112 mm | 75% | 0.4 m/s | 3.9 |
| 1993 | 23.0°C | 17.7°C | 12.5°C | 30.3°C | 3.8°C | 125 mm | 76% | 0.4 m/s | 3.5 |
| 1992 | 22.2°C | 16.9°C | 11.6°C | 28.8°C | 2.3°C | 102 mm | 76% | 0.4 m/s | 4.1 |
| 1991 | 21.4°C | 16.3°C | 11.1°C | 30.4°C | 2.3°C | 171 mm | 76% | 0.4 m/s | 4.3 |
| 1990 | 22.8°C | 17.3°C | 11.7°C | 28.8°C | 3.6°C | 58 mm | 74% | 0.4 m/s | 4.2 |
| 1989 | 22.5°C | 17.2°C | 12.0°C | 31.7°C | 2.7°C | 118 mm | 78% | 0.4 m/s | 4.3 |
| 1988 | 23.0°C | 16.9°C | 10.9°C | 28.6°C | 5.5°C | 54 mm | 69% | 0.4 m/s | 4.5 |
| 1987 | 21.9°C | 17.1°C | 12.3°C | 28.5°C | 4.3°C | 161 mm | 79% | 0.4 m/s | 3.9 |
| 1986 | 22.7°C | 16.9°C | 11.1°C | 29.5°C | 6.0°C | 30 mm | 70% | 0.4 m/s | 3.9 |
| 1985 | 22.8°C | 17.3°C | 11.8°C | 28.7°C | 5.7°C | 77 mm | 79% | 0.4 m/s | 4 |
| 1984 ❄️ | 22.1°C | 16.2°C | 10.4°C | 28.3°C | 5.1°C | 50 mm | 69% | 0.4 m/s | 4.7 |
| 1983 | 26.5°C | 19.9°C | 13.3°C | 34.5°C | 6.4°C | 43 mm | 64% | 0.4 m/s | — |
| 1982 | 23.2°C | 17.6°C | 12.0°C | 30.0°C | 8.6°C | 72 mm | 75% | 0.4 m/s | — |
| 1981 | 22.6°C | 17.0°C | 11.3°C | 29.6°C | 2.9°C | 97 mm | 72% | 0.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 23.8°C with lows near 12.9°C (mean 18.4°C), based on 45 years of NASA POWER data.
September averages 100 mm of rainfall in Brockton, about average for rainfall. The wettest on record was 216 mm in 2008.
The hottest September reached 35.6°C in 2002. The coldest dipped to 2.3°C in 1991.
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 23.4°C to 24.1°C and overnight lows from 11.8°C to 14.1°C over the same span.
September is one of the warmer months of the year in Brockton and about average for rainfall, so plan for around 23.8°C daytime highs and 12.9°C at night.
Not quite — September is the 9th coolest month in Brockton, averaging 18.4°C.
For September in Brockton, pack light layers you can adjust through the day, with typical highs of 23.8°C and lows of 12.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 75% — moderately humid.
Average wind speed in September is 0.4 m/s. The windiest September on record averaged 0.4 m/s (1981).
The wettest September on record was 2008 with 216 mm. On average, September sees 100 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 Brockton 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.
