October is one of the warmer months of the year in Sarnia, with average highs near 15.1°C and lows around 6.2°C (mean 10.7°C). It is about average for rainfall, averaging 70 mm of rainfall and 77% relative humidity across the period.
October is one of the warmer months of the year in Sarnia. Across 45 years of records, the warmest Octobers in Sarnia were 2007 and 2021 — when the month averaged 14.8°C — while the coldest was 1988 at 7.1°C. Typical October days reach 15.1°C with nights near 6.2°C. The long-term trend is warming, about 0.8°C per decade.
October is about average for rainfall in Sarnia, averaging 70 mm of rainfall. The wettest October on record was 2001 with 146 mm, while the driest was 2005 at 19 mm.
Relative humidity in Sarnia during October averages 77%. The most humid October was 1986 at 85%, and the least humid was 2024 at 70%.
October receives about 2.8 kWh/m²/day of solar energy in Sarnia. The sunniest Octobers were 2024 and 2025 at 3.4 kWh/m²/day, and the cloudiest was 2009 at 2.4.
Average wind speed in Sarnia during October is 3.7 m/s. The windiest October was 2012 at 4.5 m/s, while the calmest was 1984 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.1°C | 10.0°C | 10.7°C | 11.5°C | 12.4°C | +3.3°C |
| Avg High | 13.8°C | 14.8°C | 15.1°C | 15.6°C | 16.8°C | +3°C |
| Avg Low | 4.5°C | 5.3°C | 6.5°C | 7.4°C | 8.0°C | +3.5°C |
| Avg Rain | 70 mm | 64 mm | 64 mm | 85 mm | 65 mm | -4 mm |
October temperatures in Sarnia have risen by about 3.2°C between 1981–1985 and 2021–2025.
October has ranged from a record low of -4.5°C (1981) to a record high of 30.3°C (2007).
Rainfall in October is about average for rainfall, averaging 70 mm, with a wettest year of 146 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.7°C per decade while lows rose 0.9°C per decade, narrowing the gap between day and night.
A good time to visit Sarnia
October is a good time to visit Sarnia, with days averaging 15.1°C and nights around 6.2°C (mean 10.7°C, warmer than Sarnia's yearly average) and moderate rainfall. July and August are marginally more temperate, but October still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 17.8°C | 13.0°C | 8.2°C | 29.0°C | 1.1°C | 57 mm | 74% | 3.4 m/s | 3.4 |
| 2024 | 18.1°C | 13.1°C | 8.1°C | 24.6°C | 3.9°C | 50 mm | 70% | 3.4 m/s | 3.4 |
| 2023 | 15.9°C | 12.2°C | 8.5°C | 27.3°C | -3.0°C | 82 mm | 78% | 3.7 m/s | 2.5 |
| 2022 | 16.1°C | 11.2°C | 6.2°C | 23.4°C | 1.6°C | 43 mm | 72% | 3.8 m/s | 3.2 |
| 2021 | 18.5°C | 14.8°C | 11.1°C | 25.2°C | 4.4°C | 104 mm | 82% | 3.4 m/s | 2.5 |
| 2020 | 14.2°C | 10.0°C | 5.7°C | 23.4°C | -2.0°C | 57 mm | 76% | 3.9 m/s | 2.7 |
| 2019 | 15.4°C | 11.2°C | 7.0°C | 25.6°C | 1.4°C | 120 mm | 82% | 3.9 m/s | 2.8 |
| 2018 | 14.4°C | 10.2°C | 6.0°C | 26.9°C | -0.9°C | 98 mm | 80% | 4 m/s | 2.6 |
| 2017 | 17.6°C | 13.4°C | 9.2°C | 25.8°C | 1.3°C | 89 mm | 78% | 3.9 m/s | 2.8 |
| 2016 | 16.8°C | 12.7°C | 8.6°C | 25.3°C | 0.8°C | 69 mm | 80% | 3.6 m/s | 3 |
| 2015 | 15.4°C | 11.3°C | 7.2°C | 22.4°C | 0.9°C | 69 mm | 76% | 4.2 m/s | 2.8 |
| 2014 | 14.8°C | 10.7°C | 6.6°C | 21.4°C | 2.0°C | 61 mm | 80% | 3.8 m/s | 2.6 |
| 2013 | 16.0°C | 11.7°C | 7.4°C | 24.3°C | 0.5°C | 74 mm | 80% | 3.6 m/s | 3 |
| 2012 | 14.9°C | 11.0°C | 7.1°C | 22.3°C | 1.6°C | 114 mm | 77% | 4.5 m/s | 2.5 |
| 2011 | 15.3°C | 11.3°C | 7.3°C | 25.4°C | 1.9°C | 92 mm | 80% | 3.6 m/s | 2.7 |
| 2010 | 15.8°C | 11.7°C | 7.6°C | 22.6°C | 1.4°C | 63 mm | 74% | 4 m/s | 3.2 |
| 2009 | 13.4°C | 9.5°C | 5.6°C | 19.0°C | -0.2°C | 80 mm | 78% | 3.9 m/s | 2.4 |
| 2008 | 14.7°C | 10.3°C | 6.0°C | 24.6°C | -1.4°C | 30 mm | 74% | 3.8 m/s | 3.2 |
| 2007 🔥 | 19.2°C | 14.8°C | 10.4°C | 30.3°C | 2.4°C | 49 mm | 75% | 3.9 m/s | 3 |
| 2006 | 13.1°C | 8.8°C | 4.5°C | 23.9°C | -1.0°C | 95 mm | 79% | 4.1 m/s | 2.6 |
| 2005 | 16.5°C | 12.3°C | 8.2°C | 27.5°C | 1.0°C | 19 mm | 77% | 3.5 m/s | 3 |
| 2004 | 15.7°C | 11.5°C | 7.4°C | 23.2°C | 2.6°C | 67 mm | 78% | 3.8 m/s | 2.8 |
| 2003 | 13.9°C | 9.3°C | 4.7°C | 24.5°C | 0.4°C | 53 mm | 76% | 3.3 m/s | 2.9 |
| 2002 | 13.3°C | 9.0°C | 4.7°C | 28.0°C | -0.9°C | 46 mm | 74% | 3.3 m/s | 2.7 |
| 2001 🌧️ | 14.1°C | 9.9°C | 5.8°C | 23.5°C | -1.3°C | 146 mm | 78% | 4.2 m/s | 2.6 |
| 2000 | 16.6°C | 11.9°C | 7.2°C | 23.9°C | 2.0°C | 60 mm | 77% | 3.3 m/s | 2.9 |
| 1999 | 14.6°C | 9.9°C | 5.3°C | 23.5°C | 0.4°C | 44 mm | 72% | 3.8 m/s | 3 |
| 1998 | 16.7°C | 12.0°C | 7.3°C | 24.6°C | 3.4°C | 31 mm | 73% | 3.6 m/s | 3.2 |
| 1997 | 15.2°C | 10.6°C | 6.0°C | 26.6°C | -3.4°C | 48 mm | 76% | 3.6 m/s | 3.1 |
| 1996 | 14.5°C | 9.7°C | 5.0°C | 22.0°C | -2.2°C | 62 mm | 80% | 3.9 m/s | 2.7 |
| 1995 | 15.4°C | 10.7°C | 6.0°C | 24.6°C | 0.7°C | 83 mm | 76% | 4.2 m/s | 2.6 |
| 1994 | 15.5°C | 10.6°C | 5.8°C | 21.2°C | 1.1°C | 48 mm | 76% | 3.1 m/s | 3 |
| 1993 | 13.2°C | 8.1°C | 3.1°C | 23.2°C | -2.3°C | 62 mm | 77% | 3.8 m/s | 2.8 |
| 1992 | 13.2°C | 8.3°C | 3.5°C | 21.4°C | -2.2°C | 53 mm | 79% | 3.4 m/s | 2.8 |
| 1991 | 15.2°C | 10.8°C | 6.4°C | 24.3°C | -2.2°C | 102 mm | 74% | 3.7 m/s | 2.8 |
| 1990 | 14.3°C | 9.4°C | 4.6°C | 24.6°C | -2.3°C | 110 mm | 77% | 3.9 m/s | 2.9 |
| 1989 | 15.3°C | 10.0°C | 4.7°C | 22.7°C | -2.4°C | 51 mm | 76% | 3.6 m/s | 2.9 |
| 1988 ❄️ | 11.0°C | 7.1°C | 3.2°C | 24.3°C | -3.8°C | 94 mm | 75% | 3.9 m/s | 2.7 |
| 1987 | 11.6°C | 7.2°C | 2.8°C | 18.4°C | -1.7°C | 70 mm | 76% | 3.3 m/s | 2.9 |
| 1986 | 13.8°C | 9.2°C | 4.6°C | 19.8°C | -2.4°C | 65 mm | 85% | 3 m/s | 2.6 |
| 1985 | 14.3°C | 9.7°C | 5.1°C | 19.4°C | -0.9°C | 89 mm | 78% | 3.3 m/s | 2.7 |
| 1984 | 16.3°C | 11.5°C | 6.7°C | 20.9°C | 1.2°C | 51 mm | 78% | 2.8 m/s | 2.9 |
| 1983 | 14.2°C | 9.6°C | 5.0°C | 24.3°C | -0.6°C | 78 mm | 76% | 3.5 m/s | — |
| 1982 | 15.3°C | 10.1°C | 5.0°C | 23.6°C | -2.5°C | 29 mm | 73% | 3.1 m/s | — |
| 1981 | 12.0°C | 7.8°C | 3.5°C | 17.9°C | -4.5°C | 102 mm | 81% | 3.8 m/s | — |
Actual recorded October data for each year, 1981–2025 — sourced from NASA POWER.
The average high in October is around 15.1°C with lows near 6.2°C (mean 10.7°C), based on 45 years of NASA POWER data.
October averages 70 mm of rainfall in Sarnia, about average for rainfall. The wettest on record was 146 mm in 2001.
The hottest October reached 30.3°C in 2007. The coldest dipped to -4.5°C in 1981.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average October temperatures have risen by about 3.2°C. Daytime highs moved from 14.4°C to 17.3°C and overnight lows from 5.1°C to 8.4°C over the same span.
October is one of the warmer months of the year in Sarnia and about average for rainfall, so plan for around 15.1°C daytime highs and 6.2°C at night.
Not quite — October is the 7th coolest month in Sarnia, averaging 10.7°C.
For October in Sarnia, pack warm layers and a jacket for chilly mornings, with typical highs of 15.1°C and lows of 6.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in October averages 77% — quite humid.
Average wind speed in October is 3.7 m/s. The windiest October on record averaged 4.5 m/s (2012).
The wettest October on record was 2001 with 146 mm. On average, October sees 70 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 Sarnia behaves each October, 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 October specifically, along with year-by-year records and how the month has changed over the decades.
