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St. John's in September: Weather, Average temperature and Climate

Take a look at past year’s weather for St. John's in September and see if it is worth visiting.
Check flight prices to St. John's on Avionero:
September

Weather in St. John's in September 2025

OK Weather
Mild
🌧️
Rainy
St. John's in September usually sees fair weather conditions, with an average daily high temperature of +16°C and roughly 2 sunny days. However, you should prepare for about 16 rainy days with an average precipitation of 100 mm. The weather is changeable so pack for every eventuality. Search flights in one click on Avionero.

Average weather

☀️
+16°C
Avg. max. temperature
+2°C
Min.
+27°C
Max.
100 mm
Total precipitation
83%
Avg. humidity
5 m/s
Avg. wind
2 ☀️
Sunny Days
12 ⛅️
Cloudy
16 🌦
Rainy
Our opinion: St. John's has OK weather in September.

Average temperature in St. John's in September

Here are the expected maximum, average and minimum temperatures in St. John's for September based on the historical data.
Last Year
Historical Data

The temperature in September is +19°C on average, with a range between a maximum of +26°C during the day and a minimum of +4°C at night.

The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +16°C to +16°C.

Is St. John's warm or cold in September?

St. John's is typically mild in September.

Maximum temperatures go down compared to the previous month from +19°C to +16°C. The minimum temperature also goes down from +14°C to +11°C.

Pack a light jacket as it will be warm in the day and cool in the evenings.

September is one of the warmest months in St. John's, here is the comparison with other months:

Climate in St. John's in September

St. John's weather looks like this, on average, in September and the surrounding months.
AugustSeptemberOctober
Avg. temperature
+19°C+16°C+11°C
Min. temperature
+6°C+2°C-1°C
Max. temperature
+30°C+27°C+24°C
Rainfall
86 mm100 mm122 mm
Wind
4 m/s5 m/s5 m/s
Humidity
83%83%83%
Air pressure
1014 HPa1015 HPa1014 HPa
Sunny days
121
Cloudy days
141211
Rainy days
161619
Snowy days
000

September weather is still as ok as in August. It’s getting colder in September. From +19°C in the day, the average maximum temperature lowers to +16°C. Prepare for more rain. Average rainfall goes from 86 mm to 100 mm. Humidity levels don’t change as the month goes on, averaging around 83%. Winds are stronger in comparison to August, going up from 4 m/s to 5 m/s on average. The good news is there are likely to be more sunny days in September, from 1 to 2.

October brings much the same weather, it remains ok.

Wind

Wind speed in St. John's in September based on historical data.
Last Year
Historical Data

The average wind speed is 5 m/s getting up to 9 m/s which is a medium breeze. You can feel it, especially getting out of the water.

The average wind speed in St. John's is gradually decreasing during September, going from 4 m/s to 2 m/s over the course of the month.

Rain

Amount of rainfall in mm during September in St. John's based on historical data.
Last Year
Historical Data
A chance of rain on a typical day in September stands at 57%, leading to total precipitation of around 96 mm. The maximum amount of rainfall per day is around 18 mm, which is considered light rain. September is a pretty wet month with over 17 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of galoshes.
Here’s how September is compared with other months in the amount of precipitation, total mm:
St. John's wettest month is April, where a typical day has a 20% chance of precipitation and 126 mm of rainfall per day. February, on the other hand, is the driest month with a mere 7% chance of precipitation and 37 mm of rainfall per day.

How was the weather last September in St. John's?

This is the weather in St. John's in September 2024:
1 September
☁️
+16°C
2 September
☀️
+20°C
3 September
☁️
+23°C
4 September
☁️
+21°C
5 September
🌫️
+18°C
6 September
🌫️
+25°C
7 September
☁️
+25°C
8 September
🌧️
+20°C
9 September
☁️
+18°C
10 September
🌫️
+25°C
11 September
🌫️
+20°C
12 September
🌫️
+15°C
13 September
🌫️
+17°C
14 September
🌫️
+18°C
15 September
🌧️
+23°C
16 September
🌫️
+23°C
17 September
🌫️
+26°C
18 September
☁️
+20°C
19 September
🌫️
+15°C
20 September
🌫️
+21°C
21 September
☁️
+16°C
22 September
🌧️
+10°C
23 September
☀️
+17°C
24 September
☁️
+15°C
25 September
☁️
+13°C
26 September
☁️
+15°C
27 September
☁️
+12°C
28 September
☁️
+14°C
29 September
☀️
+19°C
30 September
☀️
+16°C
In September 2024 St. John's had 4 sunny days, 12 cloudy days, and 3 rainy days. The average maximum temperature was +19°C, with an absolute maximum of +26°C and a minimum of +10°C. The average humidity was 88%, with a maximum of 100% and a minimum of 55%. The average wind speed was 5 m/s, with a maximum of 13 m/s and a minimum of 0 m/s.
Are you planning a trip in September?

Climate Change over Years

This is how St. John's climate have been changing during last 43 years period.

The climate in St. John's in September has not changed much over the last 43 years.

The average temperature was the lowest in 1985 (+7°C) and the highest in 2022 (+11°C). The driest year was 1989 with only 563 mm of rainfall, and the wettest year was 2023 with 7230 mm.

FAQ

Frequently asked questions about the weather in St. John's in September:

Is September a good time to visit St. John's?

It’s always a good time to visit St. John's, but the weather is changeable in September, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.

Can you sunbathe in St. John's in September?

September has mild temperatures in St. John's. Not ideal for sunbathing, but still good for daytime outdoor activities, but plan for cool evenings. Pack a light jacket and shorts!

Is St. John's rainy in September?

St. John's is often rainy in September. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.

Is it sunny in St. John's in September?

Usually, it’s not very sunny in St. John's in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.

Other cities in Canada

Check out the weather for other cities in Canada.

Monthly weather in St. John's

Source of the data

For this page, we’ve looked at the typical weather in St. John's, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.