September weather forecastSaint John, Canada
September
Weather in September
September in Saint John, Canada starts to indicate the shift from the summer season towards autumn. The temperature drops moderately but the weather is still generally pleasant. While daylight hours decrease, the month allows for abundant sunshine, appeasing those who enjoy the outdoors. It's also a time when the city dresses in autumn colors and the first signs of leaf changes start to appear. Notably, September manifests a mild cooling down with temperatures dropping between 11.5°C (52.7°F) to 18°C (64.4°F).Temperature
Saint John in September undergoes a slight reduction in the average high-temperature, shifting from August's pleasant 21.5°C (70.7°F) to a refreshing 18°C (64.4°F). During the month of September, an average low-temperature of 11.5°C (52.7°F) is recorded in Saint John.Humidity
In Saint John, Canada, the average relative humidity in September is 81%.Rainfall
In Saint John, in September, during 9.5 rainfall days, 25mm (0.98") of precipitation is typically accumulated. Throughout the year, in Saint John, there are 122.4 rainfall days, and 390mm (15.35") of precipitation is accumulated.Snowfall
In Saint John, snow does not fall in June through October.Sea temperature
In September, the average sea temperature in Saint John is 13.2°C (55.8°F).Note: It is advised against swimming in 13.2°C (55.8°F) when it drops below 10°C (50°F). Such temperatures can cause extreme cold shock, leading to hyperventilation.
Daylight
The average length of the day in September is 12h and 31min.On the first day of September in Saint John, sunrise is at 6:46 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 7:06 pm ADT.
Sunshine
The average sunshine in September is 8.2h.UV index
In Saint John, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily maximum UV index of 4 in September translates into the following instructions:
Undertake protective steps - Recommendations to avoid sunburn are issued. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Boost your sun resistance with garments that are densely woven yet spacious.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Saint John, Canada
- Average high temperature in September: 18°C
The warmest month (with the highest average high temperature) is August (21.5°C).
The month with the lowest average high temperature is January (-1.9°C).
- Average low temperature in September: 11.5°C
The month with the highest average low temperature is August (14.3°C).
The coldest month (with the lowest average low temperature) is January (-8.6°C).
Average pressure in September
Saint John, Canada
- Average pressure in September: 1017mbar
The month with the highest atmospheric pressure is September (1017mbar).
The month with the lowest atmospheric pressure is June (1012.8mbar).
Average wind speed in September
Saint John, Canada
- Average wind speed in September: 14.3km/h
The windiest month (with the highest average wind speed) is January (19.9km/h).
The calmest month (with the lowest average wind speed) is August (12.3km/h).
Average humidity in September
Saint John, Canada
- Average humidity in September: 81%
The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are October and November (80%).
Average rainfall in September
Saint John, Canada
- Average rainfall in September: 25mm
The wettest month (with the highest rainfall) is December (43mm).
The driest month (with the least rainfall) is August (22mm).
Average rainfall days in September
Saint John, Canada
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is May (14.2 days).
The month with the least rainy days is February (5.4 days).
Average snowfall in September
Saint John, Canada
- Average snowfall in September: 0mm
The month with the highest snowfall is January (40mm).
The months with the least snowfall are June, July, August, September and October (0mm).
Average snowfall days in September
Saint John, Canada
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is March (9.6 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average sea temperature in September
Saint John, Canada
- Average sea temperature in September: 13.2°C
The best month for swimming (with the highest average sea temperature) is August (13.3°C).
The coldest month (with the lowest average sea temperature) is March (2.9°C).
Average daylight in September /
Average sunshine in September
Saint John, Canada
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 12min
The month with the most sunshine is August (Average sunshine: 9h and 30min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).
Average sunshine days in September
Saint John, Canada
- Average sunshine days in September: 18.3 days
The month with the most sunshine days is January (18.9 days).
The month with the least sunshine days is April (11.8 days).
Average UV index in September
Saint John, Canada
- Average UV index in September: 4
The months with the highest UV index are July and August (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).
Average cloud cover in September
Saint John, Canada
- Average cloud cover in September: 38
The month with the most cloud cover is February (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 36).
Average visibility in September
Saint John, Canada
- Average visibility in September: 9km
The month with the highest visibility is October (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, November and December (9km).
