September is one of the warmer months of the year in Thetford Mines, with average highs near 18.2°C and lows around 8.1°C (mean 13.2°C). It is about average for rainfall, averaging 97 mm of rainfall and 83% relative humidity across the period.
September is one of the warmer months of the year in Thetford Mines. Across 45 years of records, the warmest Septembers in Thetford Mines were 2015 and 2023 — when the month averaged 15.8°C — while the coldest was 1991 at 10.3°C. Typical September days reach 18.2°C with nights near 8.1°C. The long-term trend is warming, about 0.7°C per decade.
September is about average for rainfall in Thetford Mines, averaging 97 mm of rainfall. The wettest September on record was 1999 with 195 mm, while the driest was 2024 at 47 mm.
Relative humidity in Thetford Mines during September averages 83%. The most humid September was 2010 at 87%, and the least humid was 1995 at 79%.
September receives about 3.7 kWh/m²/day of solar energy in Thetford Mines. The sunniest September was 2025 at 4.4 kWh/m²/day, and the cloudiest was 2010 at 3.
Average wind speed in Thetford Mines during September is 0.1 m/s. The windiest Septembers were 1995, 2023 and 2025 at 0.2 m/s, while the calmest were 2021, 2022 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 | 11.9°C | 12.3°C | 13.5°C | 14.1°C | 14.3°C | +2.4°C |
| Avg High | 16.9°C | 17.3°C | 18.7°C | 19.1°C | 19.4°C | +2.5°C |
| Avg Low | 6.9°C | 7.3°C | 8.3°C | 9.0°C | 9.1°C | +2.2°C |
| Avg Rain | 99 mm | 110 mm | 84 mm | 106 mm | 78 mm | -21 mm |
September temperatures in Thetford Mines have risen by about 2.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -2.8°C (2014) to a record high of 29.2°C (1999).
Rainfall in September is about average for rainfall, averaging 97 mm, with a wettest year of 195 mm.
One of the best times to visit Thetford Mines
September is one of the best times to visit Thetford Mines. Expect days averaging 18.2°C and nights around 8.1°C (mean 13.2°C) — warmer than Thetford Mines's yearly average — with higher rainfall (97 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 | 19.7°C | 14.2°C | 8.7°C | 24.4°C | 0.1°C | 68 mm | 81% | 0.2 m/s | 4.4 |
| 2024 | 20.5°C | 15.1°C | 9.8°C | 25.4°C | 5.3°C | 47 mm | 83% | 0.1 m/s | 4.1 |
| 2023 | 20.8°C | 15.8°C | 10.7°C | 28.4°C | 4.8°C | 93 mm | 85% | 0.2 m/s | 3.7 |
| 2022 | 18.1°C | 13.1°C | 8.1°C | 25.7°C | 1.2°C | 103 mm | 83% | 0.1 m/s | 3.8 |
| 2021 | 19.3°C | 14.5°C | 9.7°C | 24.6°C | 5.6°C | 102 mm | 84% | 0.1 m/s | 3.5 |
| 2020 | 18.1°C | 12.8°C | 7.5°C | 24.4°C | 0.1°C | 55 mm | 80% | 0.1 m/s | 3.6 |
| 2019 | 17.7°C | 12.8°C | 7.9°C | 24.3°C | -0.1°C | 110 mm | 84% | 0.1 m/s | 3.5 |
| 2018 | 19.8°C | 14.6°C | 9.3°C | 26.8°C | -2.1°C | 91 mm | 83% | 0.1 m/s | 3.8 |
| 2017 | 20.8°C | 15.7°C | 10.6°C | 27.9°C | 3.4°C | 73 mm | 84% | 0.1 m/s | 3.9 |
| 2016 | 19.7°C | 14.5°C | 9.3°C | 26.2°C | 0.6°C | 49 mm | 82% | 0.1 m/s | 4.1 |
| 2015 🔥 | 21.2°C | 15.8°C | 10.5°C | 27.0°C | 1.1°C | 129 mm | 83% | 0.1 m/s | 4.2 |
| 2014 | 18.3°C | 13.1°C | 7.8°C | 26.4°C | -2.8°C | 68 mm | 84% | 0.1 m/s | 3.6 |
| 2013 | 17.2°C | 12.3°C | 7.5°C | 27.3°C | 0.6°C | 123 mm | 84% | 0.1 m/s | 3.6 |
| 2012 | 18.4°C | 13.0°C | 7.6°C | 24.7°C | 1.3°C | 105 mm | 82% | 0.1 m/s | 3.9 |
| 2011 | 20.0°C | 15.2°C | 10.4°C | 26.5°C | 3.1°C | 143 mm | 85% | 0.1 m/s | 3.6 |
| 2010 | 17.9°C | 13.7°C | 9.5°C | 28.2°C | 3.5°C | 167 mm | 87% | 0.1 m/s | 3 |
| 2009 | 17.8°C | 12.4°C | 6.9°C | 22.7°C | 0.1°C | 49 mm | 82% | 0.1 m/s | 4.2 |
| 2008 | 18.8°C | 13.7°C | 8.6°C | 26.6°C | 0.1°C | 77 mm | 84% | 0.1 m/s | 3.5 |
| 2007 | 18.8°C | 13.7°C | 8.5°C | 27.1°C | 2.0°C | 94 mm | 82% | 0.1 m/s | 4 |
| 2006 | 17.8°C | 12.7°C | 7.6°C | 22.7°C | 2.3°C | 74 mm | 84% | 0.1 m/s | 3.4 |
| 2005 | 19.3°C | 14.2°C | 9.1°C | 26.2°C | 2.5°C | 127 mm | 84% | 0.1 m/s | 3.6 |
| 2004 | 18.9°C | 13.4°C | 7.9°C | 23.3°C | 2.3°C | 68 mm | 82% | 0.1 m/s | 4 |
| 2003 | 20.1°C | 14.7°C | 9.3°C | 26.4°C | 3.5°C | 62 mm | 83% | 0.1 m/s | 3.9 |
| 2002 | 20.0°C | 14.6°C | 9.1°C | 27.7°C | 1.5°C | 112 mm | 82% | 0.1 m/s | 4.1 |
| 2001 | 18.4°C | 13.7°C | 8.9°C | 27.3°C | 1.1°C | 59 mm | 83% | 0.1 m/s | 3.9 |
| 2000 | 16.7°C | 11.8°C | 6.9°C | 25.2°C | -0.9°C | 118 mm | 83% | 0.1 m/s | 3.4 |
| 1999 🌧️ | 20.4°C | 15.6°C | 10.7°C | 29.2°C | 4.2°C | 195 mm | 84% | 0.1 m/s | 3.6 |
| 1998 | 18.5°C | 13.4°C | 8.4°C | 24.4°C | 1.0°C | 93 mm | 83% | 0.1 m/s | 3.5 |
| 1997 | 17.4°C | 12.4°C | 7.4°C | 22.7°C | -0.1°C | 64 mm | 84% | 0.1 m/s | 3.1 |
| 1996 | 18.2°C | 13.3°C | 8.4°C | 25.6°C | 1.4°C | 96 mm | 84% | 0.1 m/s | 3.6 |
| 1995 | 16.4°C | 10.6°C | 4.8°C | 22.6°C | -1.7°C | 87 mm | 79% | 0.2 m/s | 3.8 |
| 1994 | 16.6°C | 12.1°C | 7.6°C | 21.5°C | 3.6°C | 89 mm | 86% | 0.1 m/s | 3.3 |
| 1993 | 16.4°C | 11.6°C | 6.8°C | 24.8°C | -0.9°C | 135 mm | 82% | 0.1 m/s | 3.4 |
| 1992 | 17.8°C | 12.5°C | 7.2°C | 25.3°C | -1.7°C | 127 mm | 82% | 0.1 m/s | 3.6 |
| 1991 ❄️ | 15.4°C | 10.3°C | 5.2°C | 23.5°C | -1.1°C | 99 mm | 82% | 0.1 m/s | 3.7 |
| 1990 | 16.3°C | 11.5°C | 6.7°C | 23.0°C | 0.6°C | 119 mm | 84% | 0.1 m/s | 3.2 |
| 1989 | 17.9°C | 12.7°C | 7.5°C | 27.5°C | -1.4°C | 95 mm | 83% | 0.1 m/s | 3.7 |
| 1988 | 16.1°C | 11.2°C | 6.2°C | 23.0°C | 0.8°C | 71 mm | 83% | 0.1 m/s | 3.5 |
| 1987 | 16.3°C | 11.7°C | 7.2°C | 22.8°C | -0.2°C | 115 mm | 86% | 0.1 m/s | 3.3 |
| 1986 | 15.8°C | 10.7°C | 5.6°C | 22.1°C | -0.6°C | 143 mm | 84% | 0.1 m/s | 3.4 |
| 1985 | 18.1°C | 12.7°C | 7.3°C | 24.0°C | 3.0°C | 103 mm | 84% | 0.1 m/s | 4 |
| 1984 | 15.7°C | 10.5°C | 5.3°C | 23.0°C | -0.5°C | 51 mm | 81% | 0.1 m/s | 3.7 |
| 1983 | 18.7°C | 13.4°C | 8.2°C | 25.8°C | 1.5°C | 78 mm | 82% | 0.1 m/s | — |
| 1982 | 17.5°C | 12.7°C | 7.9°C | 24.5°C | 2.5°C | 94 mm | 86% | 0.1 m/s | — |
| 1981 | 16.1°C | 11.5°C | 6.9°C | 23.6°C | -0.1°C | 143 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 18.2°C with lows near 8.1°C (mean 13.2°C), based on 45 years of NASA POWER data.
September averages 97 mm of rainfall in Thetford Mines, about average for rainfall. The wettest on record was 195 mm in 1999.
The hottest September reached 29.2°C in 1999. The coldest dipped to -2.8°C in 2014.
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 17.2°C to 19.7°C and overnight lows from 7.1°C to 9.4°C over the same span.
September is one of the warmer months of the year in Thetford Mines and about average for rainfall, so plan for around 18.2°C daytime highs and 8.1°C at night.
Not quite — September is the 9th coolest month in Thetford Mines, averaging 13.2°C.
For September in Thetford Mines, pack light layers you can adjust through the day, with typical highs of 18.2°C and lows of 8.1°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 0.2 m/s (1995).
The wettest September on record was 1999 with 195 mm. On average, September sees 97 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 Thetford Mines 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.
