August in Saint John averages a daily high of 20.9°C with nights around 12.6°C. Expect roughly 9.9 wet days totalling 79.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Saint John is July–September.
Based on POINT LEPREAU CS, NB CA (38.3km), 1995–2024. 28 years of August data.