September is one of the warmer months of the year in Grande Prairie, with average highs near 16.4°C and lows around 5°C (mean 10.7°C). It is about average for rainfall, averaging 49 mm of rainfall and 72% relative humidity across the period.
September is one of the warmer months of the year in Grande Prairie. Across 45 years of records, the warmest September in Grande Prairie was 2025 — when the month averaged 15.1°C — while the coldest was 2018 at 5.1°C. Typical September days reach 16.4°C with nights near 5°C. The long-term trend is warming, about 0.5°C per decade.
September is about average for rainfall in Grande Prairie, averaging 49 mm of rainfall. The wettest September on record was 1985 with 112 mm, while the driest was 1995 at 8 mm.
Relative humidity in Grande Prairie during September averages 72%. The most humid September was 2019 at 83%, and the least humid was 2012 at 61%.
September receives about 3.3 kWh/m²/day of solar energy in Grande Prairie. The sunniest September was 2012 at 3.9 kWh/m²/day, and the cloudiest was 2018 at 2.7.
Average wind speed in Grande Prairie during September is 0.9 m/s. The windiest September was 2004 at 1.1 m/s, while the calmest were 2018, 2023 and 2025, among others at 0.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.6°C | 10.9°C | 10.5°C | 10.5°C | 12.7°C | +3.1°C |
| Avg High | 15.2°C | 16.8°C | 16.1°C | 16.2°C | 18.5°C | +3.3°C |
| Avg Low | 4.0°C | 4.9°C | 4.9°C | 4.9°C | 6.9°C | +2.9°C |
| Avg Rain | 58 mm | 43 mm | 54 mm | 53 mm | 35 mm | -23 mm |
September temperatures in Grande Prairie have risen by about 4.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -6.1°C (2018) to a record high of 32.8°C (1988).
Rainfall in September is about average for rainfall, averaging 49 mm, with a wettest year of 112 mm.
One of the best times to visit Grande Prairie
September is one of the best times to visit Grande Prairie. Expect days averaging 16.4°C and nights around 5°C (mean 10.7°C) — warmer than Grande Prairie's yearly average — with moderate rainfall (49 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 🔥 | 21.2°C | 15.1°C | 9.0°C | 28.1°C | 1.7°C | 24 mm | 66% | 0.8 m/s | 3.3 |
| 2024 | 18.8°C | 13.0°C | 7.2°C | 27.9°C | 1.3°C | 44 mm | 70% | 0.9 m/s | 3.2 |
| 2023 | 18.2°C | 12.1°C | 6.0°C | 25.5°C | 2.4°C | 14 mm | 71% | 0.8 m/s | 3.6 |
| 2022 | 20.4°C | 14.0°C | 7.6°C | 30.9°C | 0.6°C | 39 mm | 67% | 0.9 m/s | 3.8 |
| 2021 | 16.4°C | 11.1°C | 5.7°C | 21.9°C | 1.1°C | 57 mm | 74% | 1 m/s | 3.4 |
| 2020 | 16.1°C | 11.1°C | 6.1°C | 24.2°C | 0.9°C | 32 mm | 78% | 0.9 m/s | 3.3 |
| 2019 | 14.4°C | 9.9°C | 5.5°C | 25.3°C | -5.4°C | 72 mm | 83% | 0.9 m/s | 3 |
| 2018 ❄️ | 9.8°C | 5.1°C | 0.4°C | 21.7°C | -6.1°C | 59 mm | 81% | 0.8 m/s | 2.7 |
| 2017 | 17.3°C | 11.7°C | 6.0°C | 29.5°C | -1.9°C | 104 mm | 74% | 0.8 m/s | 3.3 |
| 2016 | 15.6°C | 10.1°C | 4.6°C | 21.8°C | -0.4°C | 39 mm | 75% | 1 m/s | 3.4 |
| 2015 | 15.5°C | 9.9°C | 4.2°C | 26.5°C | -0.1°C | 44 mm | 71% | 0.8 m/s | 3.3 |
| 2014 | 16.6°C | 10.9°C | 5.1°C | 27.0°C | -3.8°C | 84 mm | 75% | 0.8 m/s | 3.1 |
| 2013 | 20.1°C | 13.6°C | 7.1°C | 31.5°C | -1.4°C | 27 mm | 68% | 0.8 m/s | 3.8 |
| 2012 | 20.5°C | 13.7°C | 7.0°C | 27.8°C | 2.9°C | 25 mm | 61% | 1 m/s | 3.9 |
| 2011 | 18.0°C | 12.1°C | 6.1°C | 26.5°C | 0.5°C | 25 mm | 72% | 0.9 m/s | 3.4 |
| 2010 | 13.8°C | 8.4°C | 2.9°C | 24.4°C | -3.2°C | 53 mm | 75% | 0.8 m/s | 3.2 |
| 2009 | 19.9°C | 13.7°C | 7.5°C | 28.9°C | -1.2°C | 47 mm | 66% | 1 m/s | 3.4 |
| 2008 | 16.8°C | 11.1°C | 5.5°C | 24.8°C | -2.6°C | 48 mm | 73% | 0.9 m/s | 3.3 |
| 2007 | 15.2°C | 9.8°C | 4.3°C | 23.4°C | -3.7°C | 31 mm | 71% | 0.9 m/s | 3.4 |
| 2006 | 18.2°C | 12.3°C | 6.4°C | 31.7°C | -0.8°C | 55 mm | 68% | 0.9 m/s | 3.3 |
| 2005 | 14.8°C | 9.4°C | 4.1°C | 19.8°C | -0.1°C | 35 mm | 72% | 0.9 m/s | 3.3 |
| 2004 | 12.9°C | 8.0°C | 3.1°C | 18.5°C | -2.8°C | 110 mm | 80% | 1.1 m/s | 2.9 |
| 2003 | 16.4°C | 10.3°C | 4.3°C | 28.0°C | -3.9°C | 35 mm | 69% | 0.9 m/s | 3.3 |
| 2002 | 14.1°C | 8.9°C | 3.7°C | 24.3°C | -0.4°C | 78 mm | 75% | 0.9 m/s | 3 |
| 2001 | 18.2°C | 11.9°C | 5.7°C | 26.0°C | 0.7°C | 20 mm | 66% | 0.9 m/s | 3.7 |
| 2000 | 14.9°C | 9.7°C | 4.5°C | 21.4°C | -5.8°C | 77 mm | 78% | 1 m/s | 3.2 |
| 1999 | 17.5°C | 11.2°C | 4.9°C | 26.7°C | -2.1°C | 30 mm | 64% | 0.9 m/s | 3.3 |
| 1998 | 17.7°C | 11.5°C | 5.4°C | 25.8°C | 0.7°C | 35 mm | 65% | 0.8 m/s | 3.5 |
| 1997 | 16.8°C | 11.3°C | 5.9°C | 24.9°C | 0.4°C | 54 mm | 78% | 0.8 m/s | 3.3 |
| 1996 | 13.6°C | 8.5°C | 3.3°C | 23.7°C | -2.9°C | 67 mm | 77% | 0.8 m/s | 3.1 |
| 1995 | 19.8°C | 12.9°C | 6.1°C | 26.2°C | -1.8°C | 8 mm | 65% | 0.8 m/s | 3.8 |
| 1994 | 17.8°C | 12.2°C | 6.5°C | 24.9°C | 1.3°C | 65 mm | 71% | 0.9 m/s | 3 |
| 1993 | 17.1°C | 11.0°C | 4.9°C | 25.3°C | -3.5°C | 26 mm | 66% | 0.9 m/s | 3.6 |
| 1992 | 12.1°C | 6.7°C | 1.4°C | 20.8°C | -5.3°C | 77 mm | 73% | 1 m/s | 2.9 |
| 1991 | 17.2°C | 11.3°C | 5.4°C | 25.5°C | 0.2°C | 40 mm | 71% | 0.9 m/s | 3.3 |
| 1990 | 18.6°C | 12.1°C | 5.6°C | 25.8°C | -0.6°C | 23 mm | 66% | 0.9 m/s | 3.8 |
| 1989 | 16.0°C | 10.3°C | 4.6°C | 22.8°C | -1.0°C | 61 mm | 79% | 0.8 m/s | 3.4 |
| 1988 | 16.6°C | 10.6°C | 4.6°C | 32.8°C | -2.6°C | 43 mm | 67% | 0.9 m/s | 3.3 |
| 1987 | 18.7°C | 12.7°C | 6.7°C | 25.6°C | 3.4°C | 17 mm | 71% | 0.9 m/s | 3.6 |
| 1986 | 13.8°C | 8.2°C | 2.7°C | 22.0°C | -2.9°C | 90 mm | 75% | 0.8 m/s | 3 |
| 1985 🌧️ | 12.2°C | 6.9°C | 1.7°C | 22.1°C | -4.9°C | 112 mm | 77% | 1 m/s | 2.8 |
| 1984 | 11.8°C | 6.8°C | 1.8°C | 18.9°C | -4.8°C | 88 mm | 78% | 0.8 m/s | 3 |
| 1983 | 13.0°C | 8.0°C | 3.0°C | 19.5°C | -5.0°C | 37 mm | 72% | 0.9 m/s | — |
| 1982 | 16.1°C | 10.9°C | 5.6°C | 23.8°C | -0.7°C | 46 mm | 79% | 0.8 m/s | — |
| 1981 | 18.8°C | 12.2°C | 5.6°C | 31.3°C | -1.4°C | 27 mm | 65% | 0.8 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 16.4°C with lows near 5°C (mean 10.7°C), based on 45 years of NASA POWER data.
September averages 49 mm of rainfall in Grande Prairie, about average for rainfall. The wettest on record was 112 mm in 1985.
The hottest September reached 32.8°C in 1988. The coldest dipped to -6.1°C in 2018.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 4.1°C. Daytime highs moved from 14.4°C to 19°C and overnight lows from 3.5°C to 7.1°C over the same span.
September is one of the warmer months of the year in Grande Prairie and about average for rainfall, so plan for around 16.4°C daytime highs and 5°C at night.
Not quite — September is the 9th coolest month in Grande Prairie, averaging 10.7°C.
For September in Grande Prairie, pack warm layers and a jacket for chilly mornings, with typical highs of 16.4°C and lows of 5°C.
Relative humidity in September averages 72% — moderately humid.
Average wind speed in September is 0.9 m/s. The windiest September on record averaged 1.1 m/s (2004).
The wettest September on record was 1985 with 112 mm. On average, September sees 49 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 Grande Prairie 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.
