September is one of the warmer months of the year in Fredericton, with average highs near 19°C and lows around 8.6°C (mean 13.8°C). It is about average for rainfall, averaging 93 mm of rainfall and 84% relative humidity across the period.
September is one of the warmer months of the year in Fredericton. Across 45 years of records, the warmest September in Fredericton was 1999 — when the month averaged 16.7°C — while the coldest was 1986 at 10.9°C. Typical September days reach 19°C with nights near 8.6°C. The long-term trend is warming, about 0.6°C per decade.
September is about average for rainfall in Fredericton, averaging 93 mm of rainfall. The wettest September on record was 1999 with 229 mm, while the driest was 2024 at 34 mm.
Relative humidity in Fredericton during September averages 84%. The most humid September was 2013 at 87%, and the least humid was 1995 at 80%.
September receives about 3.9 kWh/m²/day of solar energy in Fredericton. The sunniest September was 2025 at 4.5 kWh/m²/day, and the cloudiest were 1996, 1997 and 2010, among others at 3.3.
Average wind speed in Fredericton during September is 0.1 m/s. The windiest Septembers were 2022, 2023 and 2025, among others at 0.2 m/s, while the calmest were 2016, 2021 and 2024, 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 | 12.7°C | 13.2°C | 13.9°C | 14.5°C | 15.1°C | +2.4°C |
| Avg High | 17.8°C | 18.3°C | 19.2°C | 19.6°C | 20.4°C | +2.6°C |
| Avg Low | 7.6°C | 8.1°C | 8.5°C | 9.3°C | 9.9°C | +2.3°C |
| Avg Rain | 92 mm | 104 mm | 84 mm | 96 mm | 86 mm | -6 mm |
September temperatures in Fredericton have risen by about 2.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -2.5°C (1989) to a record high of 30.5°C (2010).
Rainfall in September is about average for rainfall, averaging 93 mm, with a wettest year of 229 mm.
One of the best times to visit Fredericton
September is one of the best times to visit Fredericton. Expect days averaging 19°C and nights around 8.6°C (mean 13.8°C) — warmer than Fredericton's yearly average — with higher rainfall (93 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 | 21.0°C | 15.0°C | 9.0°C | 25.3°C | 2.2°C | 41 mm | 81% | 0.2 m/s | 4.5 |
| 2024 | 20.8°C | 15.7°C | 10.6°C | 26.9°C | 7.9°C | 34 mm | 84% | 0.1 m/s | 4.2 |
| 2023 | 21.9°C | 16.5°C | 11.1°C | 28.4°C | 4.0°C | 133 mm | 86% | 0.2 m/s | 3.7 |
| 2022 | 19.3°C | 14.4°C | 9.5°C | 27.3°C | 2.0°C | 92 mm | 83% | 0.2 m/s | 3.9 |
| 2021 | 19.8°C | 15.2°C | 10.7°C | 24.7°C | 6.2°C | 167 mm | 86% | 0.1 m/s | 3.6 |
| 2020 | 19.3°C | 13.8°C | 8.2°C | 25.1°C | 0.5°C | 48 mm | 82% | 0.2 m/s | 4 |
| 2019 | 18.2°C | 12.9°C | 7.7°C | 23.7°C | 1.0°C | 136 mm | 84% | 0.2 m/s | 4 |
| 2018 | 19.7°C | 14.1°C | 8.5°C | 26.7°C | -0.9°C | 55 mm | 83% | 0.2 m/s | 4.1 |
| 2017 | 21.6°C | 16.3°C | 11.0°C | 28.2°C | 2.3°C | 55 mm | 85% | 0.2 m/s | 4 |
| 2016 | 19.9°C | 14.6°C | 9.3°C | 26.7°C | 1.4°C | 46 mm | 85% | 0.1 m/s | 4 |
| 2015 | 21.6°C | 16.1°C | 10.5°C | 28.7°C | 1.8°C | 163 mm | 84% | 0.1 m/s | 4.3 |
| 2014 | 19.0°C | 13.7°C | 8.3°C | 27.0°C | 0.5°C | 53 mm | 84% | 0.1 m/s | 4.2 |
| 2013 | 18.2°C | 13.5°C | 8.8°C | 25.2°C | 1.8°C | 137 mm | 87% | 0.1 m/s | 3.5 |
| 2012 | 18.7°C | 13.7°C | 8.6°C | 24.4°C | 1.8°C | 153 mm | 87% | 0.1 m/s | 3.6 |
| 2011 | 20.3°C | 15.2°C | 10.2°C | 25.2°C | 4.4°C | 43 mm | 86% | 0.2 m/s | 3.9 |
| 2010 | 19.1°C | 14.7°C | 10.2°C | 30.5°C | 3.3°C | 121 mm | 87% | 0.1 m/s | 3.3 |
| 2009 | 18.3°C | 12.8°C | 7.4°C | 24.5°C | -0.7°C | 65 mm | 83% | 0.1 m/s | 4.3 |
| 2008 | 18.7°C | 13.5°C | 8.4°C | 25.2°C | -0.3°C | 138 mm | 85% | 0.1 m/s | 3.9 |
| 2007 | 19.3°C | 13.8°C | 8.2°C | 28.2°C | 1.3°C | 56 mm | 81% | 0.2 m/s | 4.3 |
| 2006 | 18.9°C | 13.7°C | 8.5°C | 24.0°C | 3.5°C | 60 mm | 85% | 0.2 m/s | 4.1 |
| 2005 | 19.7°C | 14.7°C | 9.8°C | 25.2°C | 4.5°C | 111 mm | 85% | 0.1 m/s | 4 |
| 2004 | 18.6°C | 13.1°C | 7.6°C | 22.8°C | 3.1°C | 69 mm | 84% | 0.1 m/s | 4.2 |
| 2003 | 20.7°C | 15.4°C | 10.1°C | 27.7°C | 4.8°C | 61 mm | 85% | 0.1 m/s | 4.1 |
| 2002 | 20.2°C | 14.7°C | 9.2°C | 29.8°C | 1.2°C | 124 mm | 84% | 0.1 m/s | 3.7 |
| 2001 | 20.0°C | 14.4°C | 8.8°C | 29.3°C | 3.0°C | 87 mm | 82% | 0.2 m/s | 4.3 |
| 2000 | 17.7°C | 12.4°C | 7.1°C | 27.1°C | -1.7°C | 71 mm | 83% | 0.2 m/s | 3.9 |
| 1999 🔥 🌧️ | 21.9°C | 16.7°C | 11.5°C | 30.4°C | 4.4°C | 229 mm | 85% | 0.2 m/s | 3.8 |
| 1998 | 18.5°C | 13.7°C | 8.9°C | 24.8°C | 3.4°C | 99 mm | 85% | 0.1 m/s | 3.6 |
| 1997 | 18.0°C | 13.1°C | 8.2°C | 23.3°C | 1.5°C | 78 mm | 87% | 0.1 m/s | 3.3 |
| 1996 | 17.7°C | 13.3°C | 8.9°C | 27.3°C | 2.6°C | 109 mm | 86% | 0.2 m/s | 3.3 |
| 1995 | 17.2°C | 11.2°C | 5.3°C | 23.7°C | -1.6°C | 70 mm | 80% | 0.2 m/s | 4.3 |
| 1994 | 17.3°C | 12.5°C | 7.7°C | 22.3°C | 3.7°C | 77 mm | 85% | 0.2 m/s | 3.7 |
| 1993 | 18.3°C | 13.1°C | 7.8°C | 26.8°C | 1.8°C | 101 mm | 84% | 0.2 m/s | 3.8 |
| 1992 | 19.1°C | 13.6°C | 8.1°C | 25.5°C | -0.5°C | 43 mm | 84% | 0.1 m/s | 3.8 |
| 1991 | 17.1°C | 12.0°C | 6.9°C | 25.3°C | -0.2°C | 146 mm | 83% | 0.1 m/s | 3.8 |
| 1990 | 17.8°C | 12.7°C | 7.6°C | 24.8°C | 2.7°C | 92 mm | 86% | 0.1 m/s | 3.3 |
| 1989 | 18.2°C | 13.0°C | 7.8°C | 27.8°C | -2.5°C | 92 mm | 85% | 0.1 m/s | 4 |
| 1988 | 17.2°C | 12.2°C | 7.2°C | 24.1°C | 2.5°C | 65 mm | 82% | 0.2 m/s | 4 |
| 1987 | 17.2°C | 12.7°C | 8.3°C | 25.1°C | -0.5°C | 162 mm | 86% | 0.1 m/s | 3.6 |
| 1986 ❄️ | 16.4°C | 10.9°C | 5.5°C | 24.1°C | 0.2°C | 97 mm | 83% | 0.2 m/s | 3.8 |
| 1985 | 19.0°C | 13.6°C | 8.1°C | 26.7°C | 3.0°C | 65 mm | 83% | 0.2 m/s | 3.9 |
| 1984 | 17.1°C | 11.7°C | 6.4°C | 23.4°C | 0.7°C | 50 mm | 83% | 0.1 m/s | 4.3 |
| 1983 | 20.0°C | 14.5°C | 9.0°C | 28.1°C | 2.5°C | 63 mm | 84% | 0.1 m/s | — |
| 1982 | 18.0°C | 13.4°C | 8.7°C | 24.2°C | 3.3°C | 89 mm | 87% | 0.2 m/s | — |
| 1981 | 17.0°C | 12.4°C | 7.8°C | 23.3°C | 3.0°C | 147 mm | 85% | 0.2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 19°C with lows near 8.6°C (mean 13.8°C), based on 45 years of NASA POWER data.
September averages 93 mm of rainfall in Fredericton, about average for rainfall. The wettest on record was 229 mm in 1999.
The hottest September reached 30.5°C in 2010. The coldest dipped to -2.5°C in 1989.
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 18.2°C to 20.6°C and overnight lows from 8°C to 10.2°C over the same span.
September is one of the warmer months of the year in Fredericton and about average for rainfall, so plan for around 19°C daytime highs and 8.6°C at night.
Not quite — September is the 9th coolest month in Fredericton, averaging 13.8°C.
For September in Fredericton, pack light layers you can adjust through the day, with typical highs of 19°C and lows of 8.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 84% — quite humid.
Average wind speed in September is 0.1 m/s. The windiest September on record averaged 0.2 m/s (1981).
The wettest September on record was 1999 with 229 mm. On average, September sees 93 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 Fredericton 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.
