April is one of the cooler months of the year in Sarnia, with average highs near 12.1°C and lows around 1.5°C (mean 6.8°C). It is about average for rainfall, averaging 73 mm of rainfall and 75% relative humidity across the period.
April is one of the cooler months of the year in Sarnia. Across 45 years of records, the warmest April in Sarnia was 2010 — when the month averaged 9.6°C — while the coldest was 2018 at 2.9°C. Typical April days reach 12.1°C with nights near 1.5°C. The long-term April temperature trend is broadly flat.
April is about average for rainfall in Sarnia, averaging 73 mm of rainfall. The wettest April on record was 2013 with 153 mm, while the driest was 2021 at 20 mm.
Relative humidity in Sarnia during April averages 75%. The most humid April was 1993 at 80%, and the least humid was 2010 at 70%.
April receives about 4.7 kWh/m²/day of solar energy in Sarnia. The sunniest April was 2008 at 5.5 kWh/m²/day, and the cloudiest were 1992 and 2011 at 3.7.
Average wind speed in Sarnia during April is 4.1 m/s. The windiest Aprils were 1981 and 1982 at 4.8 m/s, while the calmest was 1989 at 3.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 6.7°C | 6.5°C | 7.2°C | 6.5°C | 7.5°C | +0.8°C |
| Avg High | 12.0°C | 11.6°C | 12.6°C | 11.7°C | 12.8°C | +0.8°C |
| Avg Low | 1.3°C | 1.3°C | 1.7°C | 1.3°C | 2.2°C | +0.9°C |
| Avg Rain | 69 mm | 77 mm | 63 mm | 87 mm | 64 mm | -5 mm |
April temperatures in Sarnia have risen by about 1.4°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -10.1°C (1982) to a record high of 26.8°C (2023).
Rainfall in April is about average for rainfall, averaging 73 mm, with a wettest year of 153 mm.
A good time to visit Sarnia
April is a good time to visit Sarnia, with days averaging 12.1°C and nights around 1.5°C (mean 6.8°C, cooler than Sarnia's yearly average) and moderate rainfall. July and August are marginally more temperate, but April still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 13.3°C | 7.6°C | 1.9°C | 25.4°C | -4.7°C | 86 mm | 71% | 4.2 m/s | 5 |
| 2024 | 14.6°C | 9.4°C | 4.2°C | 23.3°C | -2.6°C | 86 mm | 75% | 4.2 m/s | 5 |
| 2023 | 14.1°C | 8.4°C | 2.8°C | 26.8°C | -4.0°C | 78 mm | 72% | 3.6 m/s | 4.5 |
| 2022 | 10.9°C | 5.9°C | 0.8°C | 24.0°C | -3.4°C | 66 mm | 76% | 3.8 m/s | 4.4 |
| 2021 | 13.5°C | 8.3°C | 3.1°C | 25.4°C | -5.4°C | 20 mm | 72% | 3.6 m/s | 4.7 |
| 2020 | 10.4°C | 5.4°C | 0.4°C | 18.1°C | -4.2°C | 48 mm | 76% | 3.9 m/s | 4.7 |
| 2019 | 11.0°C | 6.4°C | 1.8°C | 18.1°C | -7.9°C | 109 mm | 80% | 4.3 m/s | 4.3 |
| 2018 ❄️ | 7.5°C | 2.9°C | -1.7°C | 18.9°C | -6.8°C | 82 mm | 77% | 3.8 m/s | 4.6 |
| 2017 | 14.6°C | 9.2°C | 3.8°C | 23.2°C | -3.0°C | 108 mm | 80% | 4.3 m/s | 4.6 |
| 2016 | 9.8°C | 4.8°C | -0.3°C | 23.5°C | -6.8°C | 56 mm | 75% | 3.7 m/s | 4.7 |
| 2015 | 12.1°C | 6.5°C | 1.0°C | 20.4°C | -5.8°C | 65 mm | 76% | 4 m/s | 4.5 |
| 2014 | 12.2°C | 6.5°C | 0.8°C | 21.8°C | -5.5°C | 75 mm | 75% | 4.1 m/s | 4.8 |
| 2013 🌧️ | 10.5°C | 5.4°C | 0.4°C | 21.9°C | -4.8°C | 153 mm | 78% | 4.3 m/s | 4.2 |
| 2012 | 12.2°C | 7.0°C | 1.8°C | 20.3°C | -1.2°C | 48 mm | 74% | 4.1 m/s | 5.1 |
| 2011 | 11.1°C | 6.3°C | 1.4°C | 22.9°C | -2.1°C | 113 mm | 80% | 4.6 m/s | 3.7 |
| 2010 🔥 | 15.8°C | 9.6°C | 3.5°C | 24.6°C | -2.1°C | 58 mm | 70% | 4 m/s | 4.9 |
| 2009 | 12.5°C | 7.0°C | 1.6°C | 23.5°C | -4.1°C | 128 mm | 76% | 4.6 m/s | 4.8 |
| 2008 | 14.5°C | 8.5°C | 2.6°C | 22.6°C | -4.9°C | 37 mm | 72% | 3.9 m/s | 5.5 |
| 2007 | 11.2°C | 6.2°C | 1.3°C | 23.0°C | -6.0°C | 50 mm | 73% | 4.5 m/s | 4.6 |
| 2006 | 14.5°C | 8.6°C | 2.6°C | 22.6°C | -3.3°C | 52 mm | 72% | 3.7 m/s | 5.1 |
| 2005 | 13.2°C | 7.5°C | 1.7°C | 24.6°C | -1.1°C | 47 mm | 72% | 4.3 m/s | 5 |
| 2004 | 12.5°C | 7.4°C | 2.2°C | 23.8°C | -4.2°C | 35 mm | 73% | 4.6 m/s | 4.7 |
| 2003 | 11.1°C | 5.6°C | 0.0°C | 24.8°C | -10.1°C | 71 mm | 75% | 4.3 m/s | 4.7 |
| 2002 | 11.7°C | 6.9°C | 2.0°C | 24.2°C | -4.4°C | 74 mm | 78% | 4 m/s | 4.4 |
| 2001 | 13.4°C | 7.7°C | 1.9°C | 23.2°C | -2.5°C | 58 mm | 75% | 4.1 m/s | 4.8 |
| 2000 | 11.6°C | 6.5°C | 1.5°C | 22.3°C | -4.6°C | 78 mm | 72% | 3.8 m/s | 4.4 |
| 1999 | 13.1°C | 8.0°C | 2.8°C | 22.2°C | -0.9°C | 100 mm | 72% | 3.9 m/s | 4.7 |
| 1998 | 12.8°C | 7.7°C | 2.5°C | 18.7°C | -2.1°C | 47 mm | 72% | 3.6 m/s | 5.2 |
| 1997 | 10.4°C | 5.2°C | 0.0°C | 20.2°C | -4.9°C | 29 mm | 74% | 3.8 m/s | 5 |
| 1996 | 9.7°C | 4.6°C | -0.6°C | 20.1°C | -5.4°C | 105 mm | 76% | 4.3 m/s | 4.4 |
| 1995 | 9.6°C | 4.7°C | -0.3°C | 16.2°C | -6.3°C | 80 mm | 74% | 4.3 m/s | 4 |
| 1994 | 12.7°C | 7.1°C | 1.5°C | 24.0°C | -4.6°C | 92 mm | 73% | 4.5 m/s | 5 |
| 1993 | 11.0°C | 5.7°C | 0.5°C | 18.5°C | -6.7°C | 86 mm | 80% | 3.9 m/s | 4.2 |
| 1992 | 10.6°C | 5.7°C | 0.8°C | 20.9°C | -5.1°C | 98 mm | 79% | 3.6 m/s | 3.7 |
| 1991 | 13.6°C | 8.5°C | 3.4°C | 23.3°C | -4.1°C | 83 mm | 80% | 4.4 m/s | 4.2 |
| 1990 | 12.8°C | 7.3°C | 1.9°C | 25.8°C | -5.5°C | 54 mm | 76% | 3.8 m/s | 4.8 |
| 1989 | 10.4°C | 5.1°C | -0.2°C | 20.0°C | -5.8°C | 47 mm | 71% | 3.3 m/s | 4.7 |
| 1988 | 12.0°C | 6.4°C | 0.8°C | 19.5°C | -4.5°C | 56 mm | 75% | 4.1 m/s | 5 |
| 1987 | 13.2°C | 8.1°C | 2.9°C | 24.1°C | -7.9°C | 50 mm | 78% | 4 m/s | 4.9 |
| 1986 | 13.2°C | 7.7°C | 2.2°C | 24.8°C | -3.8°C | 64 mm | 78% | 3.8 m/s | 4.8 |
| 1985 | 14.2°C | 9.0°C | 3.7°C | 24.3°C | -5.2°C | 73 mm | 79% | 4.1 m/s | 5.3 |
| 1984 | 11.6°C | 6.7°C | 1.8°C | 21.9°C | -3.5°C | 68 mm | 79% | 3.9 m/s | 4.4 |
| 1983 | 10.0°C | 5.2°C | 0.3°C | 21.1°C | -5.0°C | 105 mm | 78% | 4.2 m/s | — |
| 1982 | 9.9°C | 4.0°C | -1.8°C | 19.0°C | -10.1°C | 44 mm | 74% | 4.8 m/s | — |
| 1981 | 13.4°C | 7.7°C | 1.9°C | 20.7°C | -4.0°C | 113 mm | 72% | 4.8 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 12.1°C with lows near 1.5°C (mean 6.8°C), based on 45 years of NASA POWER data.
April averages 73 mm of rainfall in Sarnia, about average for rainfall. The wettest on record was 153 mm in 2013.
The hottest April reached 26.8°C in 2023. The coldest dipped to -10.1°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 1.4°C. Daytime highs moved from 11.8°C to 13.3°C and overnight lows from 1.2°C to 2.6°C over the same span.
April is one of the cooler months of the year in Sarnia and about average for rainfall, so plan for around 12.1°C daytime highs and 1.5°C at night.
Not quite — April is the 6th coolest month in Sarnia, averaging 6.8°C.
For April in Sarnia, pack warm layers and a jacket for chilly mornings, with typical highs of 12.1°C and lows of 1.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in April averages 75% — quite humid.
Average wind speed in April is 4.1 m/s. The windiest April on record averaged 4.8 m/s (1981).
The wettest April on record was 2013 with 153 mm. On average, April sees 73 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 April, 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 April specifically, along with year-by-year records and how the month has changed over the decades.
