September weather forecastSaint John, VI

September
Weather in September
Despite heading towards the tail end of summer, September in Saint John brings no reprieve from the warmth. The tropical maritime climate is at its zenith during this period, with plenty of sun-soaked days to enjoy. The high point featuring September weather is the substantial increase in rainfall, registering a notable 5.6" (142mm). Locals and visitors can expect an interplay of hot sunny days and refreshing evening showers.Temperature
Saint John sees the highest average temperatures during the months of August and September, peaking at 87.8°F (31°C).Rainfall
In Saint John, during September, the rain falls for 16 days and regularly aggregates up to 5.63" (143mm) of precipitation. Throughout the year, there are 156 rainfall days, and 49.69" (1262mm) of precipitation is accumulated.Ocean temperature
September and October, with an average ocean temperature of 84.2°F (29°C), are months with the warmest seawater.Note: For engaging in any water activities, temperatures from 77°F (25°C) to 84.2°F (29°C) are viewed as outstanding and exceptionally pleasing for prolonged durations.
Daylight
The average length of the day in September is 12h and 14min.On the first day of the month, sunrise is at 6:04 am and sunset at 6:32 pm. On the last day of September, sunrise is at 6:09 am and sunset at 6:08 pm AST.
Sunshine
In Saint John, the average sunshine in September is 8h.UV index
The months with the highest UV index are March through September, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an extreme health hazard from exposure to the Sun's UV radiation for average individuals.Note: The daily maximum UV index of 12 in September interprets into the following advice:
Employ every precaution of importance, unprotected skin and eyes could burn within moments. UV radiation from the Sun is most intense between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Even if the day is cloudy, sunscreen with SPF of at least 30 should be applied generously and reapplied often, particularly after swimming or outdoor exercise. Attention! The reflection of both water and sand can increase the intensity of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Saint John, VI
- Average high temperature in September: 88°F
The warmest months (with the highest average high temperature) are August and September (88°F).
The months with the lowest average high temperature are January, February, March and December (82°F).
- Average low temperature in September: 75°F
The months with the highest average low temperature are June, July, August, September and October (75°F).
The coldest months (with the lowest average low temperature) are January, February and March (70°F).
Average rainfall in September
Saint John, VI
- Average rainfall in September: 5.6"
The wettest months (with the highest rainfall) are October and November (6.3").
The driest month (with the least rainfall) is February (2.1").
Average rainfall days in September
Saint John, VI
- Average rainfall days in September: 16 days
The months with the highest number of rainy days are September and October (16 days).
The month with the least rainy days is April (9 days).
Average sea temperature in September
Saint John, VI
- Average sea temperature in September: 84°F
The best months for swimming (with the highest average sea temperature) are September and October (84°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (79°F).
Average daylight in September /
Average sunshine in September
Saint John, VI
- Average daylight in September: 12h and 12min
The month with the longest days is June (Average daylight: 13h and 12min).
The month with the shortest days is December (Average daylight: 11h and 6min).
- Average sunshine in September: 8h
The months with the most sunshine are March, April, July and August (Average sunshine: 9h).
The months with the least sunshine are November and December (Average sunshine: 7h).
Average UV index in September
Saint John, VI
- Average UV index in September: 12
The months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
The month with the lowest UV index is December (UV index 7).





