Climate Insights for Saint John

The climate in Saint John is cool. The average annual temperature is 7°C and approximately 1356mm of precipitation falls per year. Saint John receives a notable amount of rainfall throughout the year, including during its driest month. Saint John is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, September. The coldest months are January, February, December, when temperatures can drop to -8°C. Saint John experiences heavy snowfall, typically from January through December.

Temperatures in Saint John vary considerably across the year, with a 29°C difference between the coldest and warmest months. August is the warmest month, though highs remain moderate at 21°C with a mean of 18°C. The coldest month is January, when overnight lows fall to -8°C and the daily average is -4°C. Daily temperature variation is modest, with an average difference of 6°C between highs and lows. The sharpest temperature change occurs between October and November, with a 6°C shift in average temperatures.

Saint John is a fairly wet location, receiving approximately 1356mm of precipitation annually, which averages out to around 113mm per month. The wettest month is November, averaging 152mm of rainfall. December and January also tend to see above-average precipitation. The driest month is July, with just 74mm. That's 78mm less than November, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Saint John receives heavy snowfall, accumulating around 246cm annually from January through December. The snowiest month is February, with approximately 60cm. Winter travel should account for significant snow cover.

Saint John is relatively calm, with an average annual wind speed of 5km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is January, averaging 5km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 4km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 1km/h gap between the calmest and windiest months.

It is currently summer in Saint John, which began on June 21, 2026. Saint John is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 21°C, while the coldest stretch bottoms out in January near -8°C. Autumn is next, beginning on September 23, 2026 — 92 days from now.

The best time to visit Saint John is during July and August, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 76mm per month. By contrast, January can be quite cold with temperatures dropping to -8°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Saint John based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.