August is one of the warmer months of the year in Saint John, with average highs near 22.7°C and lows around 13.3°C (mean 18°C). It is one of the drier months, averaging 88 mm of rainfall and 85% relative humidity across the period.
August is one of the warmer months of the year in Saint John. Across 45 years of records, the warmest August in Saint John was 2015 — when the month averaged 19.9°C — while the coldest was 1982 at 15.6°C. Typical August days reach 22.7°C with nights near 13.3°C. The long-term trend is warming, about 0.3°C per decade.
August is one of the drier months in Saint John, averaging 88 mm of rainfall. The wettest August on record was 1991 with 192 mm, while the driest was 2025 at 22 mm.
Relative humidity in Saint John during August averages 85%. The most humid August was 2011 at 87%, and the least humid was 2025 at 81%.
August receives about 5 kWh/m²/day of solar energy in Saint John. The sunniest August was 2025 at 5.7 kWh/m²/day, and the cloudiest were 1988 and 2008 at 4.2.
Average wind speed in Saint John during August is 0.4 m/s. The windiest Augusts were 2013, 2016 and 2020, among others at 0.5 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.3°C | 17.9°C | 17.9°C | 18.5°C | 18.7°C | +1.4°C |
| Avg High | 21.9°C | 22.7°C | 22.5°C | 23.1°C | 23.4°C | +1.5°C |
| Avg Low | 12.6°C | 13.1°C | 13.2°C | 13.9°C | 14.0°C | +1.4°C |
| Avg Rain | 108 mm | 73 mm | 86 mm | 89 mm | 86 mm | -22 mm |
August temperatures in Saint John have risen by about 1.3°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 4.6°C (1982) to a record high of 31.5°C (2025).
Rainfall in August is one of the drier months, averaging 88 mm, with a wettest year of 192 mm.
One of the best times to visit Saint John
August is one of the best times to visit Saint John. Expect days averaging 22.7°C and nights around 13.3°C (mean 18°C) — warmer than Saint John's yearly average — with higher rainfall (88 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 | 23.3°C | 17.9°C | 12.6°C | 31.5°C | 7.6°C | 22 mm | 81% | 0.4 m/s | 5.7 |
| 2024 | 23.6°C | 18.9°C | 14.3°C | 29.6°C | 9.3°C | 83 mm | 86% | 0.4 m/s | 4.9 |
| 2023 | 22.1°C | 17.8°C | 13.6°C | 25.7°C | 8.5°C | 146 mm | 87% | 0.4 m/s | 4.5 |
| 2022 | 24.0°C | 19.5°C | 14.9°C | 29.5°C | 10.7°C | 120 mm | 86% | 0.4 m/s | 4.5 |
| 2021 | 24.2°C | 19.4°C | 14.6°C | 30.3°C | 10.2°C | 86 mm | 86% | 0.4 m/s | 5.1 |
| 2020 | 23.0°C | 18.5°C | 14.0°C | 27.8°C | 7.7°C | 57 mm | 84% | 0.5 m/s | 5.3 |
| 2019 | 22.8°C | 18.0°C | 13.2°C | 26.0°C | 8.0°C | 88 mm | 85% | 0.4 m/s | 5.1 |
| 2018 | 24.3°C | 19.7°C | 15.1°C | 29.3°C | 11.0°C | 106 mm | 86% | 0.4 m/s | 5 |
| 2017 | 22.4°C | 17.6°C | 12.7°C | 26.0°C | 9.5°C | 58 mm | 85% | 0.4 m/s | 5.1 |
| 2016 | 23.3°C | 18.6°C | 13.9°C | 28.4°C | 11.0°C | 96 mm | 86% | 0.5 m/s | 4.9 |
| 2015 🔥 | 24.3°C | 19.9°C | 15.4°C | 28.3°C | 12.3°C | 85 mm | 87% | 0.4 m/s | 5.1 |
| 2014 | 22.3°C | 17.7°C | 13.1°C | 26.0°C | 8.6°C | 105 mm | 85% | 0.4 m/s | 5 |
| 2013 | 22.2°C | 17.5°C | 12.8°C | 26.6°C | 8.4°C | 80 mm | 85% | 0.5 m/s | 5.1 |
| 2012 | 24.1°C | 19.6°C | 15.1°C | 30.4°C | 10.4°C | 69 mm | 86% | 0.4 m/s | 4.9 |
| 2011 | 22.4°C | 18.1°C | 13.9°C | 25.5°C | 10.0°C | 158 mm | 87% | 0.5 m/s | 4.6 |
| 2010 | 23.0°C | 18.2°C | 13.5°C | 29.8°C | 9.8°C | 47 mm | 83% | 0.4 m/s | 5.2 |
| 2009 | 23.5°C | 18.8°C | 14.2°C | 29.2°C | 7.6°C | 144 mm | 86% | 0.4 m/s | 5.2 |
| 2008 | 21.7°C | 17.4°C | 13.0°C | 26.2°C | 9.8°C | 93 mm | 87% | 0.4 m/s | 4.2 |
| 2007 | 22.3°C | 17.3°C | 12.3°C | 27.6°C | 7.9°C | 77 mm | 84% | 0.4 m/s | 5.3 |
| 2006 | 20.8°C | 16.4°C | 11.9°C | 27.3°C | 6.8°C | 70 mm | 85% | 0.5 m/s | 4.9 |
| 2005 | 22.8°C | 17.8°C | 12.9°C | 27.2°C | 7.8°C | 94 mm | 85% | 0.4 m/s | 5 |
| 2004 | 22.3°C | 17.7°C | 13.1°C | 26.3°C | 8.3°C | 134 mm | 86% | 0.5 m/s | 4.7 |
| 2003 | 22.8°C | 18.4°C | 13.9°C | 27.0°C | 7.4°C | 107 mm | 86% | 0.4 m/s | 4.4 |
| 2002 | 23.3°C | 18.5°C | 13.6°C | 29.4°C | 7.3°C | 38 mm | 83% | 0.4 m/s | 5.4 |
| 2001 | 23.6°C | 18.6°C | 13.7°C | 27.5°C | 7.1°C | 34 mm | 83% | 0.4 m/s | 5.2 |
| 2000 | 22.3°C | 17.7°C | 13.2°C | 26.9°C | 8.8°C | 70 mm | 86% | 0.5 m/s | 4.6 |
| 1999 | 22.3°C | 17.7°C | 13.0°C | 27.3°C | 9.1°C | 75 mm | 83% | 0.5 m/s | 4.9 |
| 1998 | 23.4°C | 18.4°C | 13.4°C | 30.4°C | 8.4°C | 81 mm | 83% | 0.5 m/s | 5.3 |
| 1997 | 21.7°C | 17.1°C | 12.5°C | 26.6°C | 9.3°C | 42 mm | 85% | 0.4 m/s | 4.8 |
| 1996 | 22.8°C | 17.7°C | 12.7°C | 29.8°C | 9.1°C | 26 mm | 84% | 0.4 m/s | 5.2 |
| 1995 | 22.4°C | 17.3°C | 12.3°C | 29.3°C | 8.1°C | 50 mm | 83% | 0.5 m/s | 5.4 |
| 1994 | 22.1°C | 17.6°C | 13.1°C | 26.4°C | 8.2°C | 53 mm | 84% | 0.5 m/s | 5.2 |
| 1993 | 23.1°C | 18.1°C | 13.1°C | 29.1°C | 8.5°C | 25 mm | 83% | 0.4 m/s | 5.6 |
| 1992 | 22.1°C | 17.4°C | 12.7°C | 27.6°C | 9.0°C | 94 mm | 86% | 0.5 m/s | 4.9 |
| 1991 🌧️ | 23.0°C | 18.5°C | 13.9°C | 28.6°C | 9.0°C | 192 mm | 86% | 0.5 m/s | 4.7 |
| 1990 | 24.3°C | 19.4°C | 14.6°C | 29.2°C | 7.8°C | 91 mm | 84% | 0.4 m/s | 5.3 |
| 1989 | 21.8°C | 17.2°C | 12.5°C | 25.6°C | 6.8°C | 129 mm | 85% | 0.5 m/s | 4.6 |
| 1988 | 22.8°C | 18.2°C | 13.7°C | 29.8°C | 7.1°C | 137 mm | 86% | 0.5 m/s | 4.2 |
| 1987 | 21.7°C | 16.8°C | 11.9°C | 30.1°C | 6.4°C | 47 mm | 81% | 0.5 m/s | 5.1 |
| 1986 | 20.8°C | 16.5°C | 12.1°C | 27.8°C | 5.4°C | 138 mm | 86% | 0.5 m/s | 4.4 |
| 1985 | 21.4°C | 16.8°C | 12.1°C | 27.7°C | 7.0°C | 98 mm | 85% | 0.4 m/s | 5 |
| 1984 | 24.4°C | 19.6°C | 14.8°C | 30.7°C | 9.7°C | 76 mm | 86% | 0.4 m/s | 5 |
| 1983 | 22.4°C | 17.7°C | 13.1°C | 26.9°C | 8.3°C | 95 mm | 85% | 0.5 m/s | — |
| 1982 ❄️ | 20.0°C | 15.6°C | 11.1°C | 26.2°C | 4.6°C | 118 mm | 85% | 0.5 m/s | — |
| 1981 | 22.0°C | 17.2°C | 12.4°C | 26.7°C | 7.3°C | 131 mm | 85% | 0.5 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 22.7°C with lows near 13.3°C (mean 18°C), based on 45 years of NASA POWER data.
August averages 88 mm of rainfall in Saint John, one of the drier months. The wettest on record was 192 mm in 1991.
The hottest August reached 31.5°C in 2025. The coldest dipped to 4.6°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.3°C. Daytime highs moved from 22°C to 23.4°C and overnight lows from 12.7°C to 14°C over the same span.
August is one of the warmer months of the year in Saint John and one of the drier months, so plan for around 22.7°C daytime highs and 13.3°C at night.
Not quite — August is the 11th coolest month in Saint John, averaging 18°C.
For August in Saint John, pack light layers you can adjust through the day, with typical highs of 22.7°C and lows of 13.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 85% — quite humid.
Average wind speed in August is 0.4 m/s. The windiest August on record averaged 0.5 m/s (1981).
The wettest August on record was 1991 with 192 mm. On average, August sees 88 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 Saint John behaves each August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
