September is one of the warmer months of the year in Red Deer, with average highs near 17.4°C and lows around 5.1°C (mean 11.3°C). It is about average for rainfall, averaging 46 mm of rainfall and 69% relative humidity across the period.
September is one of the warmer months of the year in Red Deer. Across 45 years of records, the warmest September in Red Deer was 2025 — when the month averaged 16.1°C — while the coldest was 2018 at 6.2°C. Typical September days reach 17.4°C with nights near 5.1°C. The long-term trend is warming, about 0.8°C per decade.
September is about average for rainfall in Red Deer, averaging 46 mm of rainfall. The wettest September on record was 1986 with 126 mm, while the driest were 1990 and 2009 at 8 mm.
Relative humidity in Red Deer during September averages 69%. The most humid September was 2004 at 78%, and the least humid was 2009 at 55%.
September receives about 3.7 kWh/m²/day of solar energy in Red Deer. The sunniest September was 1990 at 4.4 kWh/m²/day, and the cloudiest was 2018 at 2.7.
Average wind speed in Red Deer during September is 2.5 m/s. The windiest September was 1985 at 3.1 m/s, while the calmest was 2008 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.6°C | 11.3°C | 11.1°C | 11.2°C | 13.9°C | +4.3°C |
| Avg High | 15.4°C | 17.7°C | 17.4°C | 17.1°C | 20.2°C | +4.8°C |
| Avg Low | 3.8°C | 4.9°C | 4.9°C | 5.3°C | 7.6°C | +3.8°C |
| Avg Rain | 69 mm | 38 mm | 46 mm | 43 mm | 28 mm | -41 mm |
September temperatures in Red Deer have risen by about 5.4°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -5.9°C (1985) to a record high of 32.5°C (2022).
Rainfall in September is about average for rainfall, averaging 46 mm, with a wettest year of 126 mm.
One of the best times to visit Red Deer
September is one of the best times to visit Red Deer. Expect days averaging 17.4°C and nights around 5.1°C (mean 11.3°C) — warmer than Red Deer's yearly average — with moderate rainfall (46 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 🔥 | 22.8°C | 16.1°C | 9.4°C | 30.0°C | 4.7°C | 22 mm | 65% | 2.2 m/s | 4.1 |
| 2024 | 20.5°C | 14.3°C | 8.0°C | 31.5°C | 1.6°C | 53 mm | 68% | 2.4 m/s | 4 |
| 2023 | 19.4°C | 13.4°C | 7.4°C | 26.1°C | 1.9°C | 28 mm | 66% | 2.4 m/s | 3.8 |
| 2022 | 21.9°C | 15.1°C | 8.3°C | 32.5°C | 2.2°C | 10 mm | 61% | 2.4 m/s | 4 |
| 2021 | 18.6°C | 12.5°C | 6.3°C | 24.0°C | 2.6°C | 27 mm | 66% | 2.6 m/s | 3.8 |
| 2020 | 17.9°C | 12.1°C | 6.3°C | 24.4°C | 1.0°C | 27 mm | 73% | 2.7 m/s | 3.7 |
| 2019 | 15.6°C | 10.9°C | 6.2°C | 24.0°C | -4.6°C | 52 mm | 78% | 2.3 m/s | 3.3 |
| 2018 ❄️ | 11.1°C | 6.2°C | 1.4°C | 26.7°C | -5.7°C | 57 mm | 77% | 2.3 m/s | 2.7 |
| 2017 | 18.1°C | 11.8°C | 5.5°C | 30.0°C | -0.2°C | 53 mm | 69% | 2.4 m/s | 3.5 |
| 2016 | 16.5°C | 10.9°C | 5.3°C | 24.3°C | 1.1°C | 32 mm | 72% | 2.3 m/s | 3.6 |
| 2015 | 15.6°C | 10.0°C | 4.4°C | 26.5°C | 0.2°C | 77 mm | 75% | 2.2 m/s | 3.5 |
| 2014 | 17.3°C | 11.3°C | 5.3°C | 27.0°C | -4.7°C | 42 mm | 71% | 2.4 m/s | 3.5 |
| 2013 | 20.9°C | 14.3°C | 7.7°C | 29.0°C | -0.2°C | 23 mm | 62% | 2.4 m/s | 4 |
| 2012 | 20.9°C | 14.0°C | 7.1°C | 26.4°C | 2.8°C | 18 mm | 60% | 2.6 m/s | 4.2 |
| 2011 | 21.1°C | 14.0°C | 6.9°C | 28.2°C | 2.0°C | 12 mm | 61% | 2.6 m/s | 4.2 |
| 2010 | 14.3°C | 8.9°C | 3.5°C | 23.4°C | -4.6°C | 62 mm | 75% | 2.3 m/s | 3.1 |
| 2009 | 22.6°C | 15.0°C | 7.5°C | 31.7°C | 0.2°C | 8 mm | 55% | 3 m/s | 4.2 |
| 2008 | 17.7°C | 11.2°C | 4.7°C | 25.6°C | -0.3°C | 31 mm | 69% | 2.1 m/s | 3.9 |
| 2007 | 15.6°C | 9.8°C | 3.9°C | 24.4°C | -2.8°C | 53 mm | 72% | 2.4 m/s | 3.8 |
| 2006 | 18.2°C | 12.2°C | 6.2°C | 29.9°C | -1.9°C | 77 mm | 71% | 2.6 m/s | 3.5 |
| 2005 | 14.7°C | 9.2°C | 3.7°C | 22.0°C | -1.6°C | 86 mm | 76% | 2.3 m/s | 3.3 |
| 2004 | 14.8°C | 9.4°C | 3.9°C | 21.2°C | -4.8°C | 53 mm | 78% | 2.2 m/s | 3.2 |
| 2003 | 16.7°C | 10.6°C | 4.5°C | 30.1°C | -3.8°C | 40 mm | 66% | 2.6 m/s | 3.6 |
| 2002 | 16.3°C | 10.3°C | 4.4°C | 25.8°C | -1.3°C | 48 mm | 68% | 2.5 m/s | 3.4 |
| 2001 | 20.3°C | 13.2°C | 6.1°C | 28.8°C | 2.4°C | 25 mm | 60% | 2.4 m/s | 3.7 |
| 2000 | 16.8°C | 10.4°C | 4.0°C | 24.2°C | -5.2°C | 39 mm | 70% | 2.5 m/s | 3.6 |
| 1999 | 16.7°C | 10.6°C | 4.5°C | 25.2°C | -3.1°C | 10 mm | 66% | 2.5 m/s | 4.2 |
| 1998 | 19.4°C | 12.8°C | 6.1°C | 30.5°C | -0.3°C | 30 mm | 63% | 2.4 m/s | 3.8 |
| 1997 | 18.7°C | 12.4°C | 6.1°C | 27.9°C | -2.4°C | 66 mm | 68% | 2.8 m/s | 3.9 |
| 1996 | 14.6°C | 9.6°C | 4.6°C | 27.4°C | -1.4°C | 63 mm | 72% | 2.8 m/s | 3.2 |
| 1995 | 18.9°C | 12.1°C | 5.2°C | 26.7°C | -3.8°C | 12 mm | 63% | 2.2 m/s | 4.2 |
| 1994 | 19.9°C | 13.2°C | 6.4°C | 27.0°C | 1.2°C | 46 mm | 66% | 2.3 m/s | 3.9 |
| 1993 | 16.5°C | 10.0°C | 3.5°C | 24.5°C | -3.2°C | 36 mm | 69% | 2.6 m/s | 4 |
| 1992 | 14.0°C | 7.7°C | 1.5°C | 24.9°C | -4.3°C | 82 mm | 72% | 2.6 m/s | 3.3 |
| 1991 | 18.0°C | 11.5°C | 5.0°C | 24.6°C | -1.4°C | 32 mm | 67% | 2.6 m/s | 3.9 |
| 1990 | 20.7°C | 13.4°C | 6.0°C | 27.9°C | -0.4°C | 8 mm | 62% | 2.5 m/s | 4.4 |
| 1989 | 17.4°C | 11.0°C | 4.5°C | 23.9°C | -3.8°C | 37 mm | 72% | 2.7 m/s | 4.1 |
| 1988 | 16.5°C | 10.6°C | 4.6°C | 30.0°C | -2.6°C | 70 mm | 70% | 2.6 m/s | 3.3 |
| 1987 | 19.7°C | 13.2°C | 6.6°C | 27.5°C | 1.5°C | 41 mm | 67% | 2.5 m/s | 4.2 |
| 1986 🌧️ | 12.1°C | 7.2°C | 2.4°C | 18.4°C | -3.2°C | 126 mm | 78% | 2.5 m/s | 3 |
| 1985 | 12.2°C | 6.6°C | 0.9°C | 19.3°C | -5.9°C | 75 mm | 74% | 3.1 m/s | 3.1 |
| 1984 | 12.5°C | 7.2°C | 1.8°C | 25.1°C | -5.1°C | 125 mm | 76% | 2.4 m/s | 3.3 |
| 1983 | 14.0°C | 8.4°C | 2.8°C | 25.7°C | -4.7°C | 42 mm | 73% | 2.6 m/s | — |
| 1982 | 15.8°C | 10.2°C | 4.7°C | 23.8°C | -3.1°C | 63 mm | 77% | 2.6 m/s | — |
| 1981 | 18.2°C | 11.9°C | 5.7°C | 29.9°C | -1.2°C | 42 mm | 67% | 2.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.4°C with lows near 5.1°C (mean 11.3°C), based on 45 years of NASA POWER data.
September averages 46 mm of rainfall in Red Deer, about average for rainfall. The wettest on record was 126 mm in 1986.
The hottest September reached 32.5°C in 2022. The coldest dipped to -5.9°C in 1985.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 5.4°C. Daytime highs moved from 14.5°C to 20.6°C and overnight lows from 3.2°C to 7.9°C over the same span.
September is one of the warmer months of the year in Red Deer and about average for rainfall, so plan for around 17.4°C daytime highs and 5.1°C at night.
Not quite — September is the 9th coolest month in Red Deer, averaging 11.3°C.
For September in Red Deer, pack warm layers and a jacket for chilly mornings, with typical highs of 17.4°C and lows of 5.1°C.
Relative humidity in September averages 69% — moderately humid.
Average wind speed in September is 2.5 m/s. The windiest September on record averaged 3.1 m/s (1985).
The wettest September on record was 1986 with 126 mm. On average, September sees 46 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 Red Deer 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.
