September is one of the warmer months of the year in Chilliwack, with average highs near 17.9°C and lows around 7.8°C (mean 12.9°C). It is one of the drier months, averaging 91 mm of rainfall and 79% relative humidity across the period.
September is one of the warmer months of the year in Chilliwack. Across 45 years of records, the warmest September in Chilliwack was 2022 — when the month averaged 15.2°C — while the coldest was 1983 at 9.8°C. Typical September days reach 17.9°C with nights near 7.8°C. The long-term trend is warming, about 0.3°C per decade.
September is one of the drier months in Chilliwack, averaging 91 mm of rainfall. The wettest September on record was 2021 with 204 mm, while the driest were 1991 and 2012 at 13 mm.
Relative humidity in Chilliwack during September averages 79%. The most humid September was 2010 at 88%, and the least humid was 1987 at 69%.
September receives about 3.9 kWh/m²/day of solar energy in Chilliwack. The sunniest September was 1993 at 4.6 kWh/m²/day, and the cloudiest was 2019 at 3.
Average wind speed in Chilliwack during September is 0.3 m/s. The windiest Septembers were 1999, 2008 and 2012, among others at 0.4 m/s, while the calmest were 2019, 2024 and 2025, among others at 0.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.9°C | 13.4°C | 12.4°C | 13.0°C | 13.9°C | +2°C |
| Avg High | 17.1°C | 18.8°C | 17.3°C | 17.8°C | 18.7°C | +1.6°C |
| Avg Low | 6.7°C | 8.1°C | 7.6°C | 8.2°C | 9.1°C | +2.4°C |
| Avg Rain | 91 mm | 68 mm | 82 mm | 112 mm | 106 mm | +15 mm |
September temperatures in Chilliwack have risen by about 2.5°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -1.5°C (2019) to a record high of 35.7°C (1988).
Rainfall in September is one of the drier months, averaging 91 mm, with a wettest year of 204 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
One of the best times to visit Chilliwack
September is one of the best times to visit Chilliwack. Expect days averaging 17.9°C and nights around 7.8°C (mean 12.9°C) — warmer than Chilliwack's yearly average — with higher rainfall (91 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 | 18.7°C | 14.4°C | 10.1°C | 26.8°C | 5.5°C | 118 mm | 88% | 0.2 m/s | 4 |
| 2024 | 17.6°C | 13.3°C | 9.0°C | 34.2°C | 0.5°C | 85 mm | 85% | 0.2 m/s | 3.8 |
| 2023 | 17.8°C | 12.9°C | 8.0°C | 25.8°C | 1.7°C | 81 mm | 80% | 0.3 m/s | 3.7 |
| 2022 🔥 | 21.1°C | 15.2°C | 9.3°C | 31.9°C | 5.3°C | 20 mm | 75% | 0.3 m/s | 4.2 |
| 2021 🌧️ | 16.6°C | 12.3°C | 8.0°C | 25.8°C | 3.5°C | 204 mm | 84% | 0.3 m/s | 3.3 |
| 2020 | 20.1°C | 15.0°C | 9.9°C | 29.1°C | 6.5°C | 131 mm | 81% | 0.3 m/s | 3.8 |
| 2019 | 15.9°C | 12.2°C | 8.4°C | 27.8°C | -1.5°C | 159 mm | 86% | 0.2 m/s | 3 |
| 2018 | 16.2°C | 11.8°C | 7.4°C | 25.2°C | 3.6°C | 114 mm | 83% | 0.3 m/s | 3.4 |
| 2017 | 19.7°C | 14.5°C | 9.2°C | 32.3°C | 3.3°C | 53 mm | 73% | 0.3 m/s | 3.7 |
| 2016 | 15.9°C | 11.5°C | 7.1°C | 22.4°C | 2.6°C | 92 mm | 83% | 0.3 m/s | 3.6 |
| 2015 | 16.0°C | 11.3°C | 6.7°C | 27.5°C | 2.2°C | 115 mm | 81% | 0.3 m/s | 3.7 |
| 2014 | 19.6°C | 14.2°C | 8.7°C | 28.6°C | 1.8°C | 94 mm | 76% | 0.3 m/s | 3.9 |
| 2013 | 18.4°C | 13.7°C | 9.1°C | 33.0°C | 0.9°C | 200 mm | 85% | 0.2 m/s | 3.6 |
| 2012 | 20.4°C | 14.4°C | 8.4°C | 31.5°C | 1.4°C | 13 mm | 72% | 0.4 m/s | 4.5 |
| 2011 | 19.6°C | 14.4°C | 9.2°C | 31.6°C | 3.8°C | 83 mm | 75% | 0.3 m/s | 4.1 |
| 2010 | 16.0°C | 11.6°C | 7.3°C | 25.4°C | 3.4°C | 199 mm | 88% | 0.2 m/s | 3.3 |
| 2009 | 19.1°C | 13.7°C | 8.4°C | 30.8°C | 1.4°C | 99 mm | 76% | 0.3 m/s | 4.2 |
| 2008 | 18.4°C | 12.8°C | 7.3°C | 29.8°C | 2.5°C | 35 mm | 76% | 0.4 m/s | 4.1 |
| 2007 | 15.8°C | 11.3°C | 6.9°C | 26.3°C | 1.5°C | 75 mm | 82% | 0.3 m/s | 3.6 |
| 2006 | 19.3°C | 14.0°C | 8.7°C | 30.7°C | 3.6°C | 58 mm | 73% | 0.3 m/s | 4.1 |
| 2005 | 15.2°C | 10.9°C | 6.7°C | 20.2°C | 2.1°C | 104 mm | 82% | 0.3 m/s | 3.6 |
| 2004 | 15.0°C | 11.0°C | 6.9°C | 21.6°C | 2.7°C | 141 mm | 86% | 0.3 m/s | 3.3 |
| 2003 | 19.3°C | 13.9°C | 8.5°C | 29.5°C | 3.5°C | 61 mm | 75% | 0.3 m/s | 4.1 |
| 2002 | 17.1°C | 12.1°C | 7.1°C | 24.9°C | 1.7°C | 70 mm | 77% | 0.3 m/s | 3.9 |
| 2001 | 17.6°C | 12.7°C | 7.7°C | 26.2°C | 3.4°C | 51 mm | 79% | 0.3 m/s | 4.1 |
| 2000 | 16.4°C | 11.9°C | 7.4°C | 27.2°C | -0.6°C | 122 mm | 82% | 0.3 m/s | 3.8 |
| 1999 | 18.2°C | 12.4°C | 6.6°C | 28.3°C | 0.6°C | 47 mm | 73% | 0.4 m/s | 4.3 |
| 1998 | 20.1°C | 14.8°C | 9.5°C | 26.4°C | 3.9°C | 24 mm | 73% | 0.4 m/s | 4.4 |
| 1997 | 19.1°C | 13.8°C | 8.6°C | 30.7°C | 2.6°C | 164 mm | 81% | 0.3 m/s | 3.9 |
| 1996 | 15.1°C | 10.7°C | 6.3°C | 26.2°C | -0.4°C | 119 mm | 83% | 0.3 m/s | 3.5 |
| 1995 | 20.7°C | 14.8°C | 8.9°C | 29.0°C | 4.1°C | 53 mm | 73% | 0.4 m/s | 4.5 |
| 1994 | 19.4°C | 14.3°C | 9.2°C | 28.2°C | 4.1°C | 71 mm | 75% | 0.4 m/s | 4.1 |
| 1993 | 19.2°C | 13.7°C | 8.2°C | 27.1°C | 1.5°C | 19 mm | 72% | 0.4 m/s | 4.6 |
| 1992 | 15.1°C | 10.5°C | 5.9°C | 25.8°C | -0.9°C | 137 mm | 81% | 0.3 m/s | 3.5 |
| 1991 | 20.1°C | 14.2°C | 8.3°C | 30.3°C | 3.6°C | 13 mm | 75% | 0.4 m/s | 4.4 |
| 1990 | 21.2°C | 15.1°C | 9.1°C | 29.0°C | 4.7°C | 34 mm | 71% | 0.4 m/s | 4.5 |
| 1989 | 20.3°C | 14.0°C | 7.7°C | 29.0°C | 3.6°C | 20 mm | 71% | 0.4 m/s | 4.4 |
| 1988 | 17.7°C | 12.3°C | 6.9°C | 35.7°C | 1.1°C | 119 mm | 77% | 0.3 m/s | 3.6 |
| 1987 | 20.4°C | 14.8°C | 9.2°C | 28.1°C | 3.8°C | 40 mm | 69% | 0.4 m/s | 4.1 |
| 1986 | 15.0°C | 10.4°C | 5.8°C | 23.7°C | -0.1°C | 108 mm | 82% | 0.3 m/s | 3.3 |
| 1985 | 15.2°C | 10.3°C | 5.4°C | 22.6°C | 0.1°C | 104 mm | 77% | 0.3 m/s | 3.6 |
| 1984 | 15.4°C | 10.3°C | 5.3°C | 21.7°C | 0.5°C | 114 mm | 81% | 0.3 m/s | 3.6 |
| 1983 ❄️ | 14.5°C | 9.8°C | 5.2°C | 21.0°C | -1.2°C | 110 mm | 82% | 0.3 m/s | — |
| 1982 | 17.6°C | 12.5°C | 7.4°C | 25.7°C | 0.7°C | 86 mm | 81% | 0.3 m/s | — |
| 1981 | 17.7°C | 12.6°C | 7.4°C | 32.5°C | 2.2°C | 119 mm | 79% | 0.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 17.9°C with lows near 7.8°C (mean 12.9°C), based on 45 years of NASA POWER data.
September averages 91 mm of rainfall in Chilliwack, one of the drier months. The wettest on record was 204 mm in 2021.
The hottest September reached 35.7°C in 1988. The coldest dipped to -1.5°C in 2019.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.5°C. Daytime highs moved from 16.1°C to 18.4°C and overnight lows from 6.1°C to 8.9°C over the same span.
September is one of the warmer months of the year in Chilliwack and one of the drier months, so plan for around 17.9°C daytime highs and 7.8°C at night.
Not quite — September is the 10th coolest month in Chilliwack, averaging 12.9°C.
For September in Chilliwack, pack warm layers and a jacket for chilly mornings, with typical highs of 17.9°C and lows of 7.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 79% — quite humid.
Average wind speed in September is 0.3 m/s. The windiest September on record averaged 0.4 m/s (1987).
The wettest September on record was 2021 with 204 mm. On average, September sees 91 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 Chilliwack 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.
