September is one of the cooler months of the year in Cambridge, with average highs near 15.1°C and lows around 6.5°C (mean 10.8°C). It is about average for rainfall, averaging 95 mm of rainfall and 84% relative humidity across the period.
September is one of the cooler months of the year in Cambridge. Across 45 years of records, the warmest Septembers in Cambridge were 2005 and 2023 — when the month averaged 12°C — while the coldest was 1992 at 8.7°C. Typical September days reach 15.1°C with nights near 6.5°C. The long-term September temperature trend is broadly flat.
September is about average for rainfall in Cambridge, averaging 95 mm of rainfall. The wettest September on record was 2022 with 187 mm, while the driest was 2018 at 39 mm.
Relative humidity in Cambridge during September averages 84%. The most humid September was 1992 at 88%, and the least humid was 2001 at 80%.
September receives about 3.7 kWh/m²/day of solar energy in Cambridge. The sunniest Septembers were 1990, 2018 and 2020, among others at 4.1 kWh/m²/day, and the cloudiest were 2010 and 2016 at 3.2.
Average wind speed in Cambridge during September is 2.5 m/s. The windiest September was 1981 at 3.3 m/s, while the calmest were 1982, 2007 and 2009 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 10.9°C | 10.2°C | 11.2°C | 10.7°C | 11.1°C | +0.2°C |
| Avg High | 15.1°C | 14.4°C | 15.8°C | 14.9°C | 15.4°C | +0.3°C |
| Avg Low | 6.6°C | 5.9°C | 6.6°C | 6.6°C | 6.8°C | +0.2°C |
| Avg Rain | 85 mm | 104 mm | 74 mm | 98 mm | 122 mm | +37 mm |
September temperatures in Cambridge have risen by about 0.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -1.5°C (2009) to a record high of 22°C (2023).
Rainfall in September is about average for rainfall, averaging 95 mm, with a wettest year of 187 mm.
A quieter season to visit Cambridge
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Cambridge. That said, September — with days averaging 15.1°C and nights around 6.5°C (mean 10.8°C) and higher rainfall (95 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 | 15.1°C | 11.2°C | 7.3°C | 19.8°C | 1.8°C | 121 mm | 85% | 2.9 m/s | 3.6 |
| 2024 | 15.6°C | 11.0°C | 6.3°C | 19.5°C | 0.7°C | 66 mm | 84% | 2.6 m/s | 4 |
| 2023 | 15.9°C | 12.0°C | 8.0°C | 22.0°C | 2.9°C | 167 mm | 86% | 2.8 m/s | 3.9 |
| 2022 🌧️ | 15.4°C | 11.3°C | 7.2°C | 20.6°C | 1.8°C | 187 mm | 83% | 2.1 m/s | 3.6 |
| 2021 | 15.0°C | 10.5°C | 6.0°C | 18.4°C | 1.6°C | 136 mm | 83% | 2.6 m/s | 3.7 |
| 2020 | 15.3°C | 10.6°C | 5.9°C | 20.2°C | -0.4°C | 56 mm | 82% | 2.8 m/s | 4.1 |
| 2019 | 15.2°C | 10.9°C | 6.7°C | 18.0°C | 3.1°C | 90 mm | 84% | 2.8 m/s | 3.9 |
| 2018 | 15.5°C | 11.0°C | 6.5°C | 21.2°C | 2.5°C | 39 mm | 83% | 2.1 m/s | 4.1 |
| 2017 | 14.8°C | 10.9°C | 7.1°C | 19.5°C | 2.8°C | 148 mm | 87% | 2.5 m/s | 3.7 |
| 2016 | 15.2°C | 11.4°C | 7.5°C | 18.2°C | 1.8°C | 127 mm | 87% | 2.4 m/s | 3.2 |
| 2015 | 14.1°C | 9.8°C | 5.5°C | 17.4°C | 1.7°C | 98 mm | 83% | 2.2 m/s | 4 |
| 2014 | 15.5°C | 11.1°C | 6.8°C | 18.4°C | 0.2°C | 105 mm | 85% | 2.5 m/s | 3.6 |
| 2013 | 15.2°C | 11.1°C | 7.1°C | 18.5°C | 0.3°C | 100 mm | 84% | 2.8 m/s | 3.6 |
| 2012 | 14.7°C | 10.5°C | 6.4°C | 20.5°C | -1.2°C | 88 mm | 83% | 2.7 m/s | 3.7 |
| 2011 | 14.5°C | 9.9°C | 5.3°C | 18.7°C | 0.2°C | 54 mm | 83% | 2.3 m/s | 4 |
| 2010 | 14.3°C | 10.8°C | 7.3°C | 20.1°C | 2.6°C | 133 mm | 87% | 3.2 m/s | 3.2 |
| 2009 | 16.4°C | 11.3°C | 6.3°C | 20.7°C | -1.5°C | 93 mm | 83% | 1.9 m/s | 3.8 |
| 2008 | 15.7°C | 11.2°C | 6.7°C | 19.4°C | 3.7°C | 58 mm | 83% | 2.3 m/s | 3.9 |
| 2007 | 15.7°C | 11.0°C | 6.4°C | 19.3°C | 0.8°C | 53 mm | 83% | 1.9 m/s | 3.7 |
| 2006 | 16.3°C | 11.7°C | 7.0°C | 20.8°C | 2.9°C | 41 mm | 83% | 2.1 m/s | 3.7 |
| 2005 🔥 | 16.5°C | 12.0°C | 7.4°C | 20.3°C | 1.9°C | 82 mm | 83% | 2.3 m/s | 3.7 |
| 2004 | 13.9°C | 9.7°C | 5.4°C | 17.4°C | -0.2°C | 77 mm | 84% | 2.7 m/s | 3.6 |
| 2003 | 15.6°C | 11.5°C | 7.5°C | 21.3°C | 3.7°C | 141 mm | 85% | 2.8 m/s | 3.4 |
| 2002 | 15.3°C | 10.9°C | 6.5°C | 18.2°C | 0.7°C | 77 mm | 82% | 2.7 m/s | 3.6 |
| 2001 | 16.4°C | 11.4°C | 6.5°C | 19.8°C | 1.9°C | 44 mm | 80% | 2 m/s | 3.7 |
| 2000 | 15.7°C | 10.9°C | 6.1°C | 19.9°C | 0.2°C | 71 mm | 82% | 2.4 m/s | 3.7 |
| 1999 | 16.2°C | 11.2°C | 6.1°C | 18.7°C | 0.3°C | 65 mm | 82% | 2 m/s | 4 |
| 1998 | 15.9°C | 11.4°C | 6.8°C | 19.5°C | 1.6°C | 52 mm | 83% | 2.5 m/s | 3.7 |
| 1997 | 13.9°C | 10.0°C | 6.1°C | 17.0°C | 0.0°C | 132 mm | 84% | 2.5 m/s | 3.6 |
| 1996 | 15.6°C | 11.3°C | 6.9°C | 19.8°C | 1.6°C | 129 mm | 87% | 2.3 m/s | 3.6 |
| 1995 | 15.0°C | 10.8°C | 6.6°C | 19.5°C | -0.1°C | 103 mm | 85% | 2.2 m/s | 3.7 |
| 1994 | 13.0°C | 9.2°C | 5.4°C | 17.4°C | 1.7°C | 146 mm | 87% | 2.8 m/s | 3.6 |
| 1993 | 12.9°C | 8.8°C | 4.7°C | 19.0°C | -0.6°C | 64 mm | 83% | 2.6 m/s | 3.8 |
| 1992 ❄️ | 12.5°C | 8.7°C | 4.8°C | 15.4°C | -1.0°C | 140 mm | 88% | 2.3 m/s | 3.8 |
| 1991 | 14.2°C | 10.5°C | 6.9°C | 16.5°C | 2.8°C | 115 mm | 87% | 2.4 m/s | 3.8 |
| 1990 | 14.3°C | 9.7°C | 5.1°C | 17.5°C | 0.3°C | 98 mm | 82% | 2 m/s | 4.1 |
| 1989 | 16.3°C | 11.6°C | 6.9°C | 19.8°C | -1.4°C | 67 mm | 83% | 2.2 m/s | 3.7 |
| 1988 | 15.5°C | 11.6°C | 7.8°C | 19.5°C | 0.3°C | 100 mm | 88% | 2.6 m/s | 3.4 |
| 1987 | 14.5°C | 10.6°C | 6.8°C | 18.9°C | 3.0°C | 90 mm | 85% | 3.1 m/s | 3.7 |
| 1986 | 14.6°C | 10.4°C | 6.2°C | 18.0°C | 1.1°C | 99 mm | 85% | 2.5 m/s | 3.8 |
| 1985 | 14.5°C | 10.8°C | 7.1°C | 17.9°C | 2.2°C | 86 mm | 83% | 3.1 m/s | 4.1 |
| 1984 | 15.2°C | 10.5°C | 5.9°C | 17.9°C | 1.8°C | 86 mm | 83% | 2.1 m/s | 3.9 |
| 1983 | 15.7°C | 11.2°C | 6.6°C | 18.5°C | 1.3°C | 98 mm | 84% | 2.8 m/s | — |
| 1982 | 15.7°C | 10.6°C | 5.5°C | 19.5°C | 0.5°C | 59 mm | 81% | 1.9 m/s | — |
| 1981 | 13.9°C | 10.4°C | 6.8°C | 16.9°C | 2.3°C | 83 mm | 85% | 3.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 15.1°C with lows near 6.5°C (mean 10.8°C), based on 45 years of NASA POWER data.
September averages 95 mm of rainfall in Cambridge, about average for rainfall. The wettest on record was 187 mm in 2022.
The hottest September reached 22°C in 2023. The coldest dipped to -1.5°C in 2009.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.5°C. Daytime highs moved from 15°C to 15.4°C and overnight lows from 6.4°C to 7°C over the same span.
September is one of the cooler months of the year in Cambridge and about average for rainfall, so plan for around 15.1°C daytime highs and 6.5°C at night.
Not quite — September is the 4th coolest month in Cambridge, averaging 10.8°C.
For September in Cambridge, pack warm layers and a jacket for chilly mornings, with typical highs of 15.1°C and lows of 6.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 84% — quite humid.
Average wind speed in September is 2.5 m/s. The windiest September on record averaged 3.3 m/s (1981).
The wettest September on record was 2022 with 187 mm. On average, September sees 95 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 Cambridge 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.
