September is one of the warmer months of the year in Calgary, with average highs near 17.6°C and lows around 4.3°C (mean 11°C). It is about average for rainfall, averaging 48 mm of rainfall and 66% relative humidity across the period.
September is one of the warmer months of the year in Calgary. Across 45 years of records, the warmest September in Calgary was 2025 — when the month averaged 15.4°C — while the coldest was 1985 at 5.5°C. Typical September days reach 17.6°C with nights near 4.3°C. The long-term trend is warming, about 0.7°C per decade.
September is about average for rainfall in Calgary, averaging 48 mm of rainfall. The wettest September on record was 1985 with 126 mm, while the driest was 2009 at 7 mm.
Relative humidity in Calgary during September averages 66%. The most humid September was 1986 at 78%, and the least humid was 2009 at 51%.
September receives about 3.7 kWh/m²/day of solar energy in Calgary. The sunniest Septembers were 2009 and 2012 at 4.4 kWh/m²/day, and the cloudiest was 1986 at 2.8.
Average wind speed in Calgary during September is 1 m/s. The windiest Septembers were 1985 and 2009 at 1.2 m/s, while the calmest were 2018, 2023 and 2025, among others at 0.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.1°C | 11.5°C | 10.8°C | 10.6°C | 13.5°C | +4.4°C |
| Avg High | 15.5°C | 18.6°C | 17.5°C | 17.0°C | 20.1°C | +4.6°C |
| Avg Low | 2.8°C | 4.3°C | 4.2°C | 4.3°C | 6.9°C | +4.1°C |
| Avg Rain | 65 mm | 32 mm | 55 mm | 54 mm | 29 mm | -36 mm |
September temperatures in Calgary have risen by about 5.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -10.6°C (2014) to a record high of 32.6°C (1988).
Rainfall in September is about average for rainfall, averaging 48 mm, with a wettest year of 126 mm.
One of the best times to visit Calgary
September is one of the best times to visit Calgary. Expect days averaging 17.6°C and nights around 4.3°C (mean 11°C) — warmer than Calgary's yearly average — with moderate rainfall (48 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 🔥 | 22.0°C | 15.4°C | 8.9°C | 28.2°C | 4.4°C | 13 mm | 68% | 0.9 m/s | 4 |
| 2024 | 19.7°C | 13.5°C | 7.4°C | 30.1°C | -0.3°C | 69 mm | 68% | 1 m/s | 3.8 |
| 2023 | 18.6°C | 12.4°C | 6.1°C | 27.4°C | 1.7°C | 33 mm | 66% | 0.9 m/s | 3.8 |
| 2022 | 21.3°C | 14.4°C | 7.5°C | 30.4°C | 0.1°C | 16 mm | 61% | 1 m/s | 4.1 |
| 2021 | 19.6°C | 12.7°C | 5.7°C | 26.7°C | 0.5°C | 14 mm | 59% | 1 m/s | 3.9 |
| 2020 | 19.5°C | 12.7°C | 5.8°C | 27.6°C | -1.2°C | 27 mm | 67% | 1.1 m/s | 3.6 |
| 2019 | 15.1°C | 9.9°C | 4.7°C | 24.4°C | -9.7°C | 74 mm | 75% | 1 m/s | 3.2 |
| 2018 | 13.0°C | 7.1°C | 1.3°C | 25.8°C | -5.8°C | 50 mm | 73% | 0.9 m/s | 2.9 |
| 2017 | 18.2°C | 11.4°C | 4.7°C | 29.5°C | -1.9°C | 32 mm | 64% | 1 m/s | 3.5 |
| 2016 | 16.1°C | 10.1°C | 4.2°C | 23.1°C | -0.2°C | 46 mm | 70% | 1 m/s | 3.6 |
| 2015 | 16.1°C | 9.8°C | 3.5°C | 27.0°C | -1.2°C | 70 mm | 69% | 1 m/s | 3.5 |
| 2014 | 16.5°C | 10.2°C | 3.9°C | 25.9°C | -10.6°C | 74 mm | 73% | 1 m/s | 3.6 |
| 2013 | 18.9°C | 12.7°C | 6.5°C | 28.7°C | -0.8°C | 71 mm | 66% | 1 m/s | 3.9 |
| 2012 | 21.1°C | 13.6°C | 6.1°C | 25.8°C | 0.1°C | 23 mm | 57% | 1.1 m/s | 4.4 |
| 2011 | 20.4°C | 13.1°C | 5.8°C | 27.3°C | -0.2°C | 23 mm | 60% | 1.1 m/s | 4.3 |
| 2010 | 14.4°C | 8.5°C | 2.5°C | 24.6°C | -3.8°C | 74 mm | 75% | 1 m/s | 3.1 |
| 2009 | 22.5°C | 14.5°C | 6.6°C | 30.3°C | -0.4°C | 7 mm | 51% | 1.2 m/s | 4.4 |
| 2008 | 17.5°C | 10.6°C | 3.7°C | 25.3°C | -1.2°C | 60 mm | 68% | 0.9 m/s | 3.9 |
| 2007 | 15.9°C | 9.4°C | 3.0°C | 25.6°C | -3.0°C | 56 mm | 69% | 0.9 m/s | 3.9 |
| 2006 | 18.7°C | 12.0°C | 5.4°C | 28.8°C | -2.6°C | 74 mm | 66% | 1.1 m/s | 3.7 |
| 2005 | 14.8°C | 8.9°C | 2.9°C | 22.5°C | -1.4°C | 87 mm | 72% | 1 m/s | 3.5 |
| 2004 | 15.4°C | 9.4°C | 3.5°C | 21.7°C | -3.9°C | 47 mm | 75% | 0.9 m/s | 3.1 |
| 2003 | 17.4°C | 10.8°C | 4.1°C | 30.3°C | -4.6°C | 60 mm | 64% | 1 m/s | 3.6 |
| 2002 | 15.7°C | 9.6°C | 3.6°C | 26.7°C | -1.8°C | 85 mm | 69% | 1 m/s | 3.3 |
| 2001 | 20.3°C | 12.8°C | 5.3°C | 28.5°C | 1.8°C | 20 mm | 56% | 1 m/s | 3.9 |
| 2000 | 16.8°C | 10.2°C | 3.5°C | 26.6°C | -7.6°C | 53 mm | 64% | 1 m/s | 3.6 |
| 1999 | 16.9°C | 10.1°C | 3.3°C | 25.6°C | -4.4°C | 24 mm | 62% | 1 m/s | 4.1 |
| 1998 | 21.0°C | 13.5°C | 5.9°C | 31.4°C | -0.8°C | 33 mm | 60% | 1 m/s | 4 |
| 1997 | 20.2°C | 13.1°C | 5.9°C | 28.3°C | -2.2°C | 39 mm | 62% | 1 m/s | 3.9 |
| 1996 | 14.6°C | 8.8°C | 2.9°C | 25.7°C | -3.4°C | 53 mm | 68% | 1.1 m/s | 3 |
| 1995 | 19.1°C | 12.0°C | 4.8°C | 28.3°C | -5.0°C | 34 mm | 60% | 1 m/s | 4 |
| 1994 | 21.5°C | 13.6°C | 5.8°C | 27.2°C | -0.4°C | 12 mm | 56% | 1 m/s | 3.7 |
| 1993 | 15.7°C | 9.2°C | 2.8°C | 24.8°C | -2.8°C | 36 mm | 68% | 1.1 m/s | 4 |
| 1992 | 15.5°C | 8.7°C | 2.0°C | 25.8°C | -4.7°C | 42 mm | 63% | 1.1 m/s | 3.3 |
| 1991 | 18.7°C | 11.4°C | 4.1°C | 26.8°C | -2.0°C | 40 mm | 62% | 1 m/s | 3.9 |
| 1990 | 22.5°C | 14.2°C | 5.8°C | 28.4°C | -0.4°C | 12 mm | 54% | 1 m/s | 4.3 |
| 1989 | 18.0°C | 11.1°C | 4.2°C | 24.6°C | -2.1°C | 49 mm | 66% | 1 m/s | 3.9 |
| 1988 | 17.7°C | 10.8°C | 3.9°C | 32.6°C | -5.3°C | 50 mm | 63% | 1.1 m/s | 3.1 |
| 1987 | 20.9°C | 13.3°C | 5.6°C | 28.4°C | 0.6°C | 35 mm | 58% | 1 m/s | 4.1 |
| 1986 | 11.3°C | 6.2°C | 1.2°C | 21.6°C | -3.0°C | 106 mm | 78% | 0.9 m/s | 2.8 |
| 1985 ❄️ 🌧️ | 11.5°C | 5.5°C | -0.4°C | 20.5°C | -6.6°C | 126 mm | 72% | 1.2 m/s | 3.2 |
| 1984 | 12.5°C | 6.6°C | 0.7°C | 24.4°C | -8.7°C | 89 mm | 71% | 1.1 m/s | 3.4 |
| 1983 | 14.3°C | 8.1°C | 1.8°C | 25.8°C | -5.5°C | 24 mm | 65% | 1.1 m/s | — |
| 1982 | 15.7°C | 9.6°C | 3.5°C | 26.3°C | -4.3°C | 79 mm | 71% | 1 m/s | — |
| 1981 | 17.7°C | 11.1°C | 4.5°C | 29.2°C | -2.9°C | 27 mm | 64% | 0.9 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.6°C with lows near 4.3°C (mean 11°C), based on 45 years of NASA POWER data.
September averages 48 mm of rainfall in Calgary, about average for rainfall. The wettest on record was 126 mm in 1985.
The hottest September reached 32.6°C in 1988. The coldest dipped to -10.6°C in 2014.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 5.5°C. Daytime highs moved from 14.3°C to 20.2°C and overnight lows from 2°C to 7.1°C over the same span.
September is one of the warmer months of the year in Calgary and about average for rainfall, so plan for around 17.6°C daytime highs and 4.3°C at night.
Not quite — September is the 9th coolest month in Calgary, averaging 11°C.
For September in Calgary, pack warm layers and a jacket for chilly mornings, with typical highs of 17.6°C and lows of 4.3°C.
Relative humidity in September averages 66% — moderately humid.
Average wind speed in September is 1 m/s. The windiest September on record averaged 1.2 m/s (1985).
The wettest September on record was 1985 with 126 mm. On average, September sees 48 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 Calgary 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.
