September is one of the warmer months of the year in Dieppe, with average highs near 19.4°C and lows around 9.1°C (mean 14.3°C). It is about average for rainfall, averaging 91 mm of rainfall and 83% relative humidity across the period.
September is one of the warmer months of the year in Dieppe. Across 45 years of records, the warmest September in Dieppe was 1999 — when the month averaged 17.4°C — while the coldest was 1986 at 11.1°C. Typical September days reach 19.4°C with nights near 9.1°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Dieppe, averaging 91 mm of rainfall. The wettest September on record was 1999 with 211 mm, while the driest was 1985 at 26 mm.
Relative humidity in Dieppe during September averages 83%. The most humid September was 2013 at 88%, and the least humid was 2025 at 74%.
September receives about 3.8 kWh/m²/day of solar energy in Dieppe. The sunniest September was 2025 at 4.4 kWh/m²/day, and the cloudiest were 1997 and 2010 at 3.1.
Average wind speed in Dieppe during September is 0.1 m/s. The windiest Septembers were 2023, 2024 and 2025, among others at 0.1 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.3°C | 13.8°C | 14.1°C | 14.8°C | 15.8°C | +2.5°C |
| Avg High | 18.3°C | 18.9°C | 19.4°C | 20.0°C | 21.2°C | +2.9°C |
| Avg Low | 8.2°C | 8.7°C | 8.8°C | 9.6°C | 10.3°C | +2.1°C |
| Avg Rain | 79 mm | 109 mm | 87 mm | 98 mm | 73 mm | -6 mm |
September temperatures in Dieppe have risen by about 2.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -0.9°C (1995) to a record high of 31.4°C (2010).
Rainfall in September is about average for rainfall, averaging 91 mm, with a wettest year of 211 mm.
One of the best times to visit Dieppe
September is one of the best times to visit Dieppe. Expect days averaging 19.4°C and nights around 9.1°C (mean 14.3°C) — warmer than Dieppe's yearly average — with higher rainfall (91 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 | 22.6°C | 16.0°C | 9.4°C | 27.4°C | 2.9°C | 31 mm | 74% | 0.1 m/s | 4.4 |
| 2024 | 21.0°C | 15.7°C | 10.5°C | 28.4°C | 6.7°C | 71 mm | 84% | 0.1 m/s | 3.9 |
| 2023 | 22.1°C | 16.9°C | 11.7°C | 28.6°C | 3.8°C | 82 mm | 85% | 0.1 m/s | 3.5 |
| 2022 | 20.6°C | 15.4°C | 10.2°C | 27.4°C | 2.9°C | 89 mm | 79% | 0.1 m/s | 4 |
| 2021 | 20.7°C | 15.9°C | 11.0°C | 25.7°C | 6.0°C | 105 mm | 85% | 0.1 m/s | 3.5 |
| 2020 | 20.0°C | 14.6°C | 9.2°C | 26.3°C | 1.7°C | 61 mm | 80% | 0.1 m/s | 4 |
| 2019 | 18.2°C | 13.1°C | 8.0°C | 24.8°C | 1.8°C | 132 mm | 83% | 0.1 m/s | 3.8 |
| 2018 | 20.4°C | 14.5°C | 8.7°C | 27.6°C | 0.5°C | 82 mm | 81% | 0.1 m/s | 4 |
| 2017 | 22.0°C | 16.4°C | 10.7°C | 28.8°C | 2.4°C | 65 mm | 83% | 0.1 m/s | 3.6 |
| 2016 | 19.9°C | 14.9°C | 9.9°C | 27.7°C | 0.8°C | 77 mm | 84% | 0.1 m/s | 3.8 |
| 2015 | 21.7°C | 16.2°C | 10.8°C | 27.4°C | 3.2°C | 124 mm | 85% | 0.1 m/s | 4.1 |
| 2014 | 19.4°C | 14.0°C | 8.6°C | 26.3°C | 0.9°C | 57 mm | 82% | 0.1 m/s | 4.1 |
| 2013 | 18.7°C | 13.9°C | 9.1°C | 25.8°C | 2.2°C | 116 mm | 88% | 0.1 m/s | 3.2 |
| 2012 | 19.5°C | 14.6°C | 9.8°C | 24.3°C | 2.2°C | 160 mm | 86% | 0.1 m/s | 3.6 |
| 2011 | 20.4°C | 15.3°C | 10.2°C | 24.9°C | 4.4°C | 36 mm | 85% | 0.1 m/s | 4 |
| 2010 | 19.3°C | 14.8°C | 10.3°C | 31.4°C | 3.4°C | 128 mm | 86% | 0.1 m/s | 3.1 |
| 2009 | 18.2°C | 12.8°C | 7.4°C | 24.7°C | 1.9°C | 74 mm | 84% | 0.1 m/s | 4.3 |
| 2008 | 18.4°C | 13.5°C | 8.7°C | 24.2°C | 0.1°C | 136 mm | 86% | 0.1 m/s | 3.7 |
| 2007 | 19.4°C | 14.0°C | 8.6°C | 26.9°C | 1.9°C | 79 mm | 80% | 0.1 m/s | 4.2 |
| 2006 | 19.3°C | 14.0°C | 8.7°C | 23.5°C | 4.0°C | 52 mm | 85% | 0.1 m/s | 4 |
| 2005 | 19.9°C | 15.1°C | 10.3°C | 25.6°C | 3.8°C | 102 mm | 83% | 0.1 m/s | 3.8 |
| 2004 | 18.6°C | 13.3°C | 8.0°C | 23.9°C | 1.5°C | 67 mm | 82% | 0.1 m/s | 3.9 |
| 2003 | 21.4°C | 15.9°C | 10.3°C | 27.8°C | 4.5°C | 52 mm | 83% | 0.1 m/s | 4.2 |
| 2002 | 19.9°C | 14.6°C | 9.3°C | 29.7°C | -0.7°C | 167 mm | 84% | 0.1 m/s | 3.6 |
| 2001 | 20.8°C | 14.9°C | 9.1°C | 27.4°C | 3.6°C | 57 mm | 81% | 0.1 m/s | 4.2 |
| 2000 | 18.3°C | 13.1°C | 7.8°C | 27.3°C | 0.6°C | 85 mm | 83% | 0.1 m/s | 3.9 |
| 1999 🔥 🌧️ | 22.7°C | 17.4°C | 12.1°C | 30.7°C | 5.1°C | 211 mm | 84% | 0.1 m/s | 3.7 |
| 1998 | 18.7°C | 14.0°C | 9.3°C | 24.9°C | 3.5°C | 126 mm | 85% | 0.1 m/s | 3.3 |
| 1997 | 18.2°C | 13.6°C | 9.0°C | 23.8°C | 1.9°C | 95 mm | 87% | 0.1 m/s | 3.1 |
| 1996 | 17.7°C | 13.3°C | 9.0°C | 27.7°C | 3.4°C | 185 mm | 86% | 0.1 m/s | 3.3 |
| 1995 | 18.8°C | 12.6°C | 6.4°C | 24.0°C | -0.9°C | 51 mm | 74% | 0.1 m/s | 4.3 |
| 1994 | 17.9°C | 13.0°C | 8.1°C | 22.5°C | 4.1°C | 59 mm | 84% | 0.1 m/s | 3.5 |
| 1993 | 19.2°C | 13.9°C | 8.5°C | 24.9°C | 2.2°C | 91 mm | 84% | 0.1 m/s | 3.6 |
| 1992 | 19.6°C | 14.2°C | 8.7°C | 24.3°C | 0.5°C | 33 mm | 82% | 0.1 m/s | 3.7 |
| 1991 | 17.7°C | 12.8°C | 7.9°C | 25.4°C | 0.3°C | 144 mm | 85% | 0.1 m/s | 3.5 |
| 1990 | 18.6°C | 13.4°C | 8.2°C | 24.9°C | 2.5°C | 90 mm | 84% | 0.1 m/s | 3.4 |
| 1989 | 18.8°C | 13.6°C | 8.4°C | 28.5°C | 0.0°C | 82 mm | 82% | 0.1 m/s | 3.9 |
| 1988 | 17.6°C | 12.6°C | 7.7°C | 23.7°C | 2.7°C | 52 mm | 82% | 0.1 m/s | 3.8 |
| 1987 | 17.9°C | 13.5°C | 9.2°C | 25.1°C | 0.7°C | 153 mm | 84% | 0.1 m/s | 3.4 |
| 1986 ❄️ | 16.5°C | 11.1°C | 5.7°C | 23.5°C | 0.3°C | 87 mm | 83% | 0.1 m/s | 4 |
| 1985 | 19.9°C | 14.4°C | 8.8°C | 26.3°C | 4.4°C | 26 mm | 81% | 0.1 m/s | 3.9 |
| 1984 | 17.6°C | 12.4°C | 7.2°C | 23.0°C | 1.3°C | 83 mm | 83% | 0.1 m/s | 4.1 |
| 1983 | 20.0°C | 14.8°C | 9.5°C | 27.5°C | 3.1°C | 49 mm | 83% | 0.1 m/s | — |
| 1982 | 18.7°C | 13.9°C | 9.0°C | 25.1°C | 3.6°C | 89 mm | 86% | 0.1 m/s | — |
| 1981 | 17.6°C | 13.1°C | 8.6°C | 23.7°C | 1.7°C | 92 mm | 85% | 0.1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 19.4°C with lows near 9.1°C (mean 14.3°C), based on 45 years of NASA POWER data.
September averages 91 mm of rainfall in Dieppe, about average for rainfall. The wettest on record was 211 mm in 1999.
The hottest September reached 31.4°C in 2010. The coldest dipped to -0.9°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.3°C. Daytime highs moved from 18.8°C to 21.4°C and overnight lows from 8.6°C to 10.6°C over the same span.
September is one of the warmer months of the year in Dieppe and about average for rainfall, so plan for around 19.4°C daytime highs and 9.1°C at night.
Not quite — September is the 9th coolest month in Dieppe, averaging 14.3°C.
For September in Dieppe, pack light layers you can adjust through the day, with typical highs of 19.4°C and lows of 9.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 83% — quite humid.
Average wind speed in September is 0.1 m/s. The windiest September on record averaged 0.1 m/s (1981).
The wettest September on record was 1999 with 211 mm. On average, September sees 91 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 Dieppe 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.
