St. John's
Canada
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
St. John's, Canada

The first month of the autumn, September, is still a comfortable month in St. John's, with average temperature varying between 16.5°C (61.7°F) and 8.2°C (46.8°F).

Temperature

In St. John's, the average high-temperature marginally drops, from an agreeable 20.5°C (68.9°F) in August, to an enjoyable 16.5°C (61.7°F). In St. John's, in September, the average low-temperature is 8.2°C (46.8°F).

Rainfall

In St. John's, in September, it is raining for 15.5 days, with typically 129.6mm (5.1") of accumulated precipitation. Throughout the year, in St. John's, Canada, there are 162.7 rainfall days, and 1206.5mm (47.5") of precipitation is accumulated.

Snowfall

In St. John's, Canada, snow does not fall in July through September.

Sea temperature

In September, the average sea temperature in St. John's is 11.9°C (53.4°F).
Note: At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 13°C (55.4°F) is not comfortable.

Daylight

In St. John's, Canada, the average length of the day is 12.6h.

Sunshine

In September, the average sunshine in St. John's is 5.7h.

UV index

In September, the average daily maximum UV index in St. John's is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to the UV radiation for the average person.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.

What is the temperature in September in St. John's?

The average high-temperature, in September, is 16.5°C (61.7°F), while the average low-temperature is 8.2°C (46.8°F).

How much does it rain in St. John's in September?

In St. John's, Canada, in September, it is raining for 15.5 days, with typically 129.6mm (5.1") of accumulated precipitation.

Does it snow in St. John's in September?

In St. John's, in September, it doesn't snow. In October, it regularly snows.

When it does not snow in St. John's?

In St. John's snow does not fall in July through September.

How cold is the water in September in St. John's?

In St. John's, Canada, the average seawater temperature in September is 11.9°C (53.4°F). At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 13°C (55.4°F) is not comfortable.

How many hours of daylight does St. John's have in September?

The average length of the day in September is 12.6h.

How long on average sun shines in September in St. John's?

The average sunshine in September in St. John's is 5.7h.

How high is the UV index in September in St. John's?

In St. John's, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from the exposure to the Sun's UV radiation.
Average temperature in September - St. John
  • Average high temperature in September: 16.5°C

The warmest month (with the highest average high temperature) is July (20.7°C).
The month with the lowest average high temperature is February (-1.1°C).

  • Average low temperature in September: 8.2°C

The month with the highest average low temperature is August (11.6°C).
The coldest month (with the lowest average low temperature) is February (-8.6°C).

Average rainfall in September - St. John
  • Average rainfall in September: 129.6mm

The wettest month (with the highest rainfall) is October (153.7mm).
The driest month (with the lowest rainfall) is February (61.6mm).

Average rainfall days in September - St. John
  • Average rainfall days in September: 15.5 days

The month with the highest number of rainy days is October (18.1 days).
The month with the lowest number of rainy days is February (8.6 days).

Average snowfall in September - St. John
  • Average snowfall in September: 0mm

The month with the highest snowfall is January (887mm).
Months with the lowest snowfall are July, August and September (0mm).

Average snowfall days in September - St. John
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (18.3 days).
Months with the lowest number of snowfall days are July, August and September (0 days).

Average sea temperature in September - St. John
  • Average sea temperature in September: 11.9°C

The best month for swimming (with the highest average sea temperature) is August (13.9°C).
The coldest month (with the lowest average sea temperature) is March (-0.4°C).

Average daylight in September / Average sunshine in September - St. John
  • Average daylight in September: 12.6h

The month with the longest days is June (Average daylight: 15.9h).
The month with shortest days is December (Average daylight: 8.5h).

  • Average sunshine in September: 5.7h

The month with most sunshine is July (Average sunshine: 7h).
The month with least sunshine is December (Average sunshine: 2h).

Average UV index in September - St. John
  • Average UV index in September: 5

Months with the highest UV index are June and July (UV index 7).
Months with the lowest UV index are January, November and December (UV index 1).