September is one of the warmer months of the year in Sylvan Lake, with average highs near 17.3°C and lows around 4.8°C (mean 11.1°C). It is about average for rainfall, averaging 51 mm of rainfall and 70% relative humidity across the period.
September is one of the warmer months of the year in Sylvan Lake. Across 45 years of records, the warmest September in Sylvan Lake was 2025 — when the month averaged 16.2°C — while the coldest was 2018 at 6.1°C. Typical September days reach 17.3°C with nights near 4.8°C. The long-term trend is warming, about 0.8°C per decade.
September is about average for rainfall in Sylvan Lake, averaging 51 mm of rainfall. The wettest September on record was 1986 with 132 mm, while the driest was 1990 at 9 mm.
Relative humidity in Sylvan Lake during September averages 70%. The most humid September was 2004 at 80%, and the least humid was 2009 at 56%.
September receives about 3.6 kWh/m²/day of solar energy in Sylvan Lake. The sunniest Septembers were 2011, 2012 and 2013, among others at 4.1 kWh/m²/day, and the cloudiest were 1986 and 2018 at 2.8.
Average wind speed in Sylvan Lake during September is 2.1 m/s. The windiest Septembers were 1985 and 2009 at 2.6 m/s, while the calmest were 2008 and 2015 at 1.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.4°C | 11.2°C | 10.9°C | 11.0°C | 13.8°C | +4.4°C |
| Avg High | 15.3°C | 17.8°C | 17.2°C | 17.1°C | 20.2°C | +4.9°C |
| Avg Low | 3.5°C | 4.6°C | 4.5°C | 5.0°C | 7.3°C | +3.8°C |
| Avg Rain | 74 mm | 41 mm | 53 mm | 49 mm | 28 mm | -46 mm |
September temperatures in Sylvan Lake have risen by about 5.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -6.3°C (1984) to a record high of 32.9°C (2022).
Rainfall in September is about average for rainfall, averaging 51 mm, with a wettest year of 132 mm.
One of the best times to visit Sylvan Lake
September is one of the best times to visit Sylvan Lake. Expect days averaging 17.3°C and nights around 4.8°C (mean 11.1°C) — warmer than Sylvan Lake's yearly average — with moderate rainfall (51 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 🔥 | 22.9°C | 16.2°C | 9.4°C | 30.2°C | 5.1°C | 22 mm | 66% | 1.9 m/s | 3.9 |
| 2024 | 20.3°C | 13.9°C | 7.4°C | 31.6°C | 0.6°C | 42 mm | 69% | 2.1 m/s | 3.8 |
| 2023 | 19.1°C | 13.0°C | 6.8°C | 26.2°C | 1.5°C | 26 mm | 67% | 2 m/s | 3.8 |
| 2022 | 22.1°C | 15.0°C | 7.9°C | 32.9°C | 2.4°C | 9 mm | 61% | 2.1 m/s | 4 |
| 2021 | 18.6°C | 12.3°C | 6.0°C | 24.3°C | 2.1°C | 34 mm | 67% | 2.2 m/s | 3.8 |
| 2020 | 18.3°C | 12.3°C | 6.3°C | 25.4°C | 0.4°C | 35 mm | 72% | 2.2 m/s | 3.5 |
| 2019 | 15.7°C | 10.7°C | 5.8°C | 24.6°C | -5.0°C | 54 mm | 77% | 2.1 m/s | 3.2 |
| 2018 ❄️ | 11.1°C | 6.1°C | 1.2°C | 27.0°C | -5.6°C | 66 mm | 77% | 2 m/s | 2.8 |
| 2017 | 17.9°C | 11.6°C | 5.3°C | 30.1°C | -0.9°C | 68 mm | 69% | 2 m/s | 3.5 |
| 2016 | 16.1°C | 10.4°C | 4.7°C | 23.6°C | 0.4°C | 47 mm | 73% | 2 m/s | 3.6 |
| 2015 | 15.4°C | 9.7°C | 4.0°C | 27.4°C | 0.0°C | 85 mm | 75% | 1.8 m/s | 3.4 |
| 2014 | 17.5°C | 11.2°C | 4.9°C | 27.2°C | -5.7°C | 45 mm | 71% | 2 m/s | 3.5 |
| 2013 | 21.1°C | 14.2°C | 7.4°C | 30.0°C | -0.5°C | 23 mm | 61% | 2 m/s | 4.1 |
| 2012 | 21.2°C | 14.0°C | 6.8°C | 26.5°C | 2.2°C | 19 mm | 60% | 2.2 m/s | 4.1 |
| 2011 | 21.2°C | 13.9°C | 6.6°C | 28.6°C | 1.3°C | 14 mm | 62% | 2.2 m/s | 4.1 |
| 2010 | 14.1°C | 8.6°C | 3.1°C | 24.1°C | -4.7°C | 68 mm | 76% | 1.9 m/s | 3 |
| 2009 | 22.5°C | 14.8°C | 7.1°C | 32.5°C | 0.8°C | 9 mm | 56% | 2.6 m/s | 4.1 |
| 2008 | 17.8°C | 10.9°C | 4.1°C | 26.4°C | -0.7°C | 41 mm | 70% | 1.8 m/s | 3.8 |
| 2007 | 15.6°C | 9.6°C | 3.6°C | 24.5°C | -2.8°C | 61 mm | 72% | 2 m/s | 3.8 |
| 2006 | 17.9°C | 11.9°C | 5.9°C | 29.8°C | -2.1°C | 88 mm | 73% | 2.2 m/s | 3.6 |
| 2005 | 14.2°C | 8.8°C | 3.3°C | 21.1°C | -2.6°C | 103 mm | 78% | 1.9 m/s | 3.2 |
| 2004 | 14.2°C | 8.9°C | 3.6°C | 20.8°C | -4.6°C | 69 mm | 80% | 2 m/s | 3.1 |
| 2003 | 17.0°C | 10.6°C | 4.2°C | 30.2°C | -3.9°C | 46 mm | 65% | 2.2 m/s | 3.5 |
| 2002 | 16.3°C | 10.1°C | 4.0°C | 26.2°C | -1.3°C | 54 mm | 69% | 2.1 m/s | 3.3 |
| 2001 | 20.1°C | 12.9°C | 5.7°C | 29.0°C | 2.1°C | 26 mm | 61% | 2 m/s | 3.9 |
| 2000 | 16.8°C | 10.2°C | 3.6°C | 24.9°C | -5.5°C | 39 mm | 70% | 2.1 m/s | 3.5 |
| 1999 | 16.8°C | 10.5°C | 4.2°C | 25.4°C | -3.3°C | 12 mm | 66% | 2.1 m/s | 3.9 |
| 1998 | 19.4°C | 12.6°C | 5.8°C | 29.9°C | 0.1°C | 31 mm | 65% | 2.1 m/s | 3.8 |
| 1997 | 18.6°C | 12.1°C | 5.6°C | 27.1°C | -2.3°C | 70 mm | 70% | 2.3 m/s | 3.8 |
| 1996 | 14.6°C | 9.4°C | 4.2°C | 27.7°C | -1.1°C | 71 mm | 73% | 2.4 m/s | 3.1 |
| 1995 | 18.9°C | 11.9°C | 4.9°C | 26.6°C | -4.0°C | 17 mm | 65% | 1.9 m/s | 4.1 |
| 1994 | 20.0°C | 13.0°C | 6.1°C | 26.7°C | 0.7°C | 44 mm | 66% | 2 m/s | 3.7 |
| 1993 | 16.3°C | 9.8°C | 3.3°C | 25.1°C | -3.7°C | 41 mm | 70% | 2.2 m/s | 3.8 |
| 1992 | 13.9°C | 7.6°C | 1.3°C | 24.4°C | -4.5°C | 85 mm | 72% | 2.2 m/s | 3.2 |
| 1991 | 18.5°C | 11.7°C | 4.9°C | 25.2°C | -0.7°C | 32 mm | 66% | 2.2 m/s | 3.8 |
| 1990 | 21.0°C | 13.3°C | 5.7°C | 28.5°C | 0.2°C | 9 mm | 62% | 2.1 m/s | 4.1 |
| 1989 | 17.1°C | 10.7°C | 4.3°C | 24.1°C | -3.0°C | 43 mm | 74% | 2.2 m/s | 3.9 |
| 1988 | 16.3°C | 10.3°C | 4.2°C | 30.5°C | -3.3°C | 77 mm | 71% | 2.2 m/s | 3.1 |
| 1987 | 19.8°C | 13.0°C | 6.2°C | 27.6°C | 0.6°C | 42 mm | 67% | 2.1 m/s | 4 |
| 1986 🌧️ | 11.8°C | 7.0°C | 2.2°C | 19.0°C | -3.5°C | 132 mm | 79% | 2.2 m/s | 2.8 |
| 1985 | 11.9°C | 6.2°C | 0.5°C | 19.2°C | -6.0°C | 88 mm | 76% | 2.6 m/s | 3.2 |
| 1984 | 12.5°C | 7.0°C | 1.6°C | 25.0°C | -6.3°C | 121 mm | 76% | 2.1 m/s | 3.4 |
| 1983 | 14.1°C | 8.3°C | 2.6°C | 26.6°C | -4.6°C | 55 mm | 71% | 2.2 m/s | — |
| 1982 | 15.6°C | 9.9°C | 4.3°C | 23.8°C | -3.2°C | 69 mm | 79% | 2.2 m/s | — |
| 1981 | 18.2°C | 11.8°C | 5.3°C | 31.0°C | -1.5°C | 42 mm | 68% | 2 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.3°C with lows near 4.8°C (mean 11.1°C), based on 45 years of NASA POWER data.
September averages 51 mm of rainfall in Sylvan Lake, about average for rainfall. The wettest on record was 132 mm in 1986.
The hottest September reached 32.9°C in 2022. The coldest dipped to -6.3°C in 1984.
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 14.5°C to 20.6°C and overnight lows from 2.9°C to 7.5°C over the same span.
September is one of the warmer months of the year in Sylvan Lake and about average for rainfall, so plan for around 17.3°C daytime highs and 4.8°C at night.
Not quite — September is the 9th coolest month in Sylvan Lake, averaging 11.1°C.
For September in Sylvan Lake, pack warm layers and a jacket for chilly mornings, with typical highs of 17.3°C and lows of 4.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 70% — moderately humid.
Average wind speed in September is 2.1 m/s. The windiest September on record averaged 2.6 m/s (1985).
The wettest September on record was 1986 with 132 mm. On average, September sees 51 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 Sylvan Lake 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.
